Does your son have a diagnosis of autism? What kind of support does he have in school?
There are some things classed (I think) as Executive Functions. People with autism 'tend' to have some difficulties with these functions. These are usually things like planning, sequencing, predicting outcomes, understanding time.
Now if your son has difficulties with these then he is going to need visual/written structures to help him complete tasks.
For example think of all the things you need to 'do' and 'think about' before you have a shower. Eg is the water hot? How to make it hot? How long to wait before the water is hot? (and that is even before you've got into the shower). Then you need to get undressed (where do you put the dirty clothes), get some soap, shampoo, towel, nail clippers etc, have some clean clothes ready. These things, and the planning and sequence that the task is done may not be clear to your son. If he has no real understanding of 'time' then he needs a daily schedule that includes having a shower. These sorts of things are usually looked at by an Occupational Therapist for self help skills and may be addressed by an OT in school or an Educational Psychologist.
Have you raised your concerns either with school or your doctor?
It may not be that he is necesarily getting worse, but that as he gets older these 'life skills' that other children pick up almost automatically are not being understood by your son. There are many very intelligent autistic adults who cannot make their own beds because they cannot process the planning and sequence the steps correctly.
How is he being treated by his pears or his teacher? Does he seem to be more stressed than usual?
One possability could be he is being picked on. His teachers may not be helping him and making sure he is able to pay attention and understand the assignments. I don't know if the assignments are too hard, but if he has a central auditory processing problem, he likely only hears parts of his teacher's instructions.
As far as the bladder problem, he may be too focused on something that he can't pay attention to when his body is telling him he needs to go, or it could be he is afraid to ask for a break. (if that's going on at school)