He's a handsome cat.
Prepare for a long narrative.
My wife and I have had 10 cats together thus far, all but 2 introduced to cats already in the house. Our first 2, Queen Victoria and Calamity Jane (The Grey Sisters) were adopted as 3 month old kittens in February 1983.
In June 1986 we rescued April Dancer from a parking lot on Eglin AFB, FL. She was a barely weaned kitten, 2 months old the vet said. It took about 2 weeks for Queen Victoria and Calamity Jane (aka Cammie) to accept her. Moved later that year with all 3.
In January 1988 we rescued Cerridwen Blythe from wandering our neighborhood near Offutt AFB, NE during a week of sub-zero temps. Vet said she was a little over 4 years old. Took the other girls about a month to accept her. Moved late in 1991 with all 4.
Dancer died from anaphylactic shock at the vet's in October 1992 while we lived near Wright-Patterson AFB, OH (wife was an officer in the USAF, I was in the Reserves).
Moved to Illinois with the 3 (wife's post USAF civilian job) in 1996, where Cerridwen passed in April 2000 (kidney/liver failure) followed a month later by Victoria (heart attack).
We observed Cammie and she was definitely lonely and depressed. We took in a 3 month old kitten from a co-worker of mine at the middle of July. Cammie took to Kestrel right away. Just after Thanksgiving 2001, we took in Kessie's 2 month old half sister Hildiekatt. Another almost immediate integration.
In mid September 2002 I was passing the cat room in PetsMart and saw a kitten that looked too much like Queen Victoria to pass by, especially when I saw she was an owner surrender; "kitten too active." Chesapeake was 3 months old and it took about a week for the other girls to accept her.
Kessie, Hildie and Chessie would take turns snuggling with Cammie, very heart warming to see the way they deferred to her and tried to keep her company in a way that did not tax her.
Cammie passed in March 2004 (2 bad strokes) and all was fine with the other three.
However, in May 2009 my wife told me about an older cat about to lose her home with the county pound being her destination. Her people were losing the house to foreclosure, and lost their marriage to the stress.
Teia was about 10 1/2 when we took her on 2 June 2009. She was a feral her previous people had rescued from some neighborhood kids who hurt her (dislocated both shoulders) at about 6 months of age. They got her fully vetted, including spaying, gave her a room to call her own, food, water, a clean litter box and not much attention beyond that.
Teia was still semi-feral and fearful when we adopted her. Took a few months before she would sit close enough to be touched (and then only on the head), another few before she sat on my lap for the first time and about half a year longer before I picked her up for the first time.
Eventually she and Hildie ate their meals together, if Hildie wasn't any closer than a foot or two. Teia and Kessie never got close, but Teia didn't mind seeing her around. Teia never took to Chessie being closer than 8 - 10 feet, but on occasion, Teia would sleep by my left side while Chessie slept by my right knee. Teia's previous people had a chubby grey cat (like Chessie) that picked on her, so we think there was some transference.
Teia and the other girls never socialized closely. However, there were no encounters that got worse than hissing, growling and spitting at each other. Teia was still a hermit most of the time, liked to den up in our walk in closet. She did roam the house at night and I found her going down the stairs to the cellar a few times.
Kessie passed in June 2012 (lymphoma) and we moved to the NAS Patuxent River, MD area in late summer that year (wife got a job with the Navy after being out of work 15 years due to PTSD and other effects of service connected disabilities). We moved into a 2 floor, 1-bedroom apartment (from a 3 bedroom, full basement ranch).
The move seemed to do Teia much good, she became Queen of the house, claiming the downstairs sunroom as hers, which she did not mind sharing with Hildie. Chessie was mistress of the bedroom suite upstairs. Hildie was upstairs and down as her mood struck. Teia also started going outside for the first time since being rescued in June 1999. (Our kitties have always gone out for short periods of time. ALWAYS with either me or my wife watching over them, no free-roaming.)
In late 2013 we finally found a house we could afford and moved in. Chessie died (heart attack) in January 2014 and Hildie (lymphoma) in June.
Teia was all alone and perfectly content to be sole cat.
At the end of October, we adopted 2 little boy kittens, Cooper who was 5 months and Buff who was 4 1/2 months, from a rescue near Harrisburg, PA (terrible, ongoing hoarding situation). At almost 16, Teia wasn't too keen on these really active, trying to be friendly, little critters. I do not believe that she had seen a kitten since she was a kitten. Almost 6 months later, she has come to accept them, if they don't get too close, though she doesn't seem to mind if Buff lays near her and Cooper lays just a little further away.
All introduction started the same. New kitty (kitties) was (were) isolated in their own room. Towels were put down in observed favorite spots and swapped between them every few days so they could get used to each others' scent.
With Teia being introduced to the other peer-age girls, the closed door was replaced by a baby gate (Kessie, Hildie, Chessie and Teia - all jump challenged). After a few months, the gate went away. The four of them came to an understanding of whose territory was were, without any fur flying.
With Buff and Cooper, I tried the baby gate, but both of them are fully jump-enabled. The door was shut for less and less time until now we put them in the "nursery" when Teia needs a break, or I let her go down into the finished basement as her sanctuary zone while the boys free-range the main and upper floor of the house.
Right now, Teia is eating and Buff is laying next to her. Cooper is in his favorite spot on the upstairs landing.
Patient, persistent kindness. Getting kitties used to each others' scent. Creating safe zones. Showing them all affection, giving each play time and attention. It does take some work, and the ability to be able to have an "isolation ward" for a time, but introducing an older cat to other cats is very feasible.
Sorry abt yr moms passing ms....sad to loose a mom. Thank goodness yr caring for her poor kitty, whose probably feeling the loss very deeply as well.
I'm not sure why yr letting the fact she is declawed stop you from giving her a loving home??
As long as you go abt introducing her slowly to her new home she and yours will work out just fine.
Any new cat has to be introduced slowly, the new kitten I brought to my home last fall is one example...Pip can give you pointers as well. Give new member their own room wth food/ litter and water...each one will become used to the scent of the other long before there's a visual intro.
After a week or so you can allow them a meet and greet, all under yr supervision. First time just briefly than depending on how it goes extend the times of each exposure. There maybe a few hisses to start off with, but that's natural
I've brought many new cats into my home over the years, some declawed some not...never has there been an issue, they may not exactly like one another but they have always learned to live together and share my home without issues.
Plz don't deny her a good home without trying this. Your mom would be so sad to think of her baby going to a shelter
Keep us posted. Fingers crossed