Because you're not a mother you can't offer reasonable advice? I do NOT get that. It's ignorant really. I love asking my childless friends for their input. You're good enough to care for them but cany offer your opinion?
But really, unsolicited advice isn't always welcome anyway.
Maybe you need to change your approach to sound more appealing without coming off as. Know it all of judgingher parenting. You're. Good friend and person to care enough to seek out helpful tips in dealing with these kids.
Two and Four year olds are notoriously challenging creatures. My boys are 15 months apart and in the toddler years . . . I had to stay on my toes to keep up with them. They had their moments! But they almost always came when I was preoccupied elsewhere. :>) Supervision, keeping them busy, tiring them out through out the day sure does cut down on moments in which you wonder about their future being behind bars for bad behavior! Things I did was plan ahead a lot of things to do such as setting up obstacle courses in the house, picnic in back yard, a mattress on the floor to jump on like trampoline, puzzle time, reading time, crazy animal walk time, simon says, etc. Yes, it's a little tiring but worth the better behaved kids you get than when they are untethered. Going to school means they have time that they are not supervised. What does she do then? she has to carefully planned because a 2 and 4 year old WILL find ways to entertain themselves and some not so great when bored. TV gets old. Playing by yourself at that age isn't too realistic for long stretches. Kids of that age have an attention span in the 5 yo 10 minute range. So, they switch activities often. Can she put them in a double stroller and walk to the park? I do have a car so could get out but I also walked a lot of places. Those long walks to a park can wear kids out! They behave better and sleep better!
So kids being wide awake at night while mom sleeps . . . tire them out during the day. And turn the baby monitor back on.
They are getting to the age in which preschool is possible. The 4 year old will go to kindergarten either next year or the year after which is half or full day. The two year old can go to preschool for a couple mornings a week. The interaction may be good for them. And if they could save up for a car so your friend can get them places, that seems like something worthwhile. Pay for driving lessons would be something of high priority I would think. How is she going to get to work? With kids, you really do need to be able to drive . . . doctors appointmetns, missed school bus, play dates at a friends house.
so, hopefully this gives her some ideas. All kids of this age are honorary but want boundaries to keep them in line. Apply them gently and understand that they need structure of activities and physical exercise to help them stay in control. good luck