Her health insurance should pay for her to have a home health aide. She really may not know she is pooping and when she finds it be too embarrassed to tell you, especially if she's "getting in trouble" for it. I have worked as an Advantage Aide and can tell you what she is doing is normal. Call her insurance company and find out who they recommend in your area. she should get bathing help, a nurse coming in and helping her set up a care plan, you can get respite care, and some house keeping help, her room, sheets, linens, clothes, anything that is hers they can help clean.
I worked 10 hours per week for one person doing respite care for her MIL and I got her out of bed if she wanted, gave her showers, washed her laundry, cleaned her bathroom and then kitchen because I fixed her lunch and was allowed to wash whatever dishes were there if time allowed. It never was more than a handful.
I also worked for another lady and we went in every morning, 7 days per week, she lived alone though, and fixed breakfast, started laundry or whatever was needed, then another staff went and fixed lunch, switched out washer and dryer, then another went and fixed her dinner and finished up what ever tasks were designated for that day. On weekends they went of a morning then again at lunch, they fixed something like stew or soup so she could heat it up in the microwave for dinner. She was able to live at home. We dumped her med container for that time frame and day into her hand and she swallowed them while we watched.
My point is that in both situations a care giver is able to do many things that are contracted to the person. If you need more time for yourself then you need to get some assistance. You need more personal time than just a few hours to go to school. You need time to go take a nap, read a book, take a bubble bath, etc...that's what respite care should help you have, normal time to your self too.
If this is not an option then perhaps moving her to a supported living facility would be in her best interest. She would have 24 hour staff but still be able to have independence.
She obviously isn't in her total right mind. Stroke does that, people change drastically after and half the time don't remember what was going on while they were getting better. She may never get her mental facilities back. She needs to be working on all areas of her therapy so it is natural for her to have the resources a home health agency can provide for her.