Why does my Mother (84) sleep all day?

Sorry I didn't know what I was doing, so here is my response. And thanks to all that replied before.
I am new to AgingCare and wasn't sure how it worked. My mom moved in with me about a year ago. At that time she was self sufficient. She had an Anoxic Brain Injury 6 years earlier and left her with a speech impairment (can totally understand you but a lot of trouble getting her words out) and some right side weakness and A-Fib. However she was still getting along but slowly going down hill. I took over her finances about 2 years ago and she gave up her car as well. In October of 2014, she ended up in the hospital with Pneumonia, which turned into an A-Fib event and after a month of the hospital we ended up at Rehab because the hospital did not give Physical Therapy. Now she can't walk and her speaking was pretty bad. She came home and we had Home Care with PT, OT and Speech. She did really well with that and we seemed to be moving in the right direction until she got a UTI. Then it has been down hill since then. It took the doctor 3 weeks to put her on the right antibiotic and by then, she couldn't walk, talk, didn't know who we were, very confused, etc. She ended up in the hospital where they said her UTI was clear, and keeping her there for "lack to thrive". She also had Congestive Heart Failure. They put her on Lasix and she slept the whole time, 24/7 for a week. They discharged her to my home even though she couldn't walk, talk or anything. We got a Hospital Bed, a Commode and a Wheel Chair. Again we had Home Care come in but it was only for a short time. Now she is totally dependent on the Wheel Chair and sleeps most of the day. She has had a few episodes like she is freezing and then it seems like she had a stroke but didn't. This past week and a half have be torture on me as well as her. She also wasn't sleeping all night long so I would get up every night to help her to the commode. I finally got an Aide that comes 12 hours a day (started on June 1st), but sometimes they just don't show up and its all up to me. I can't lift her because she is dead weight and my husband wants no part of putting her on the potty. She still gets up to go potty and her pull ups are dry. Ever since the Aide started, she has been sleeping thru the night so thats a plus, but now she sleeps pretty much all day. I try to keep her awake from 4:30pm until 8:00pm when I put her to bed. This week however, I am struggling to keep her awake and we are having trouble taking our medicine. She seems to drift off and stare up at the ceiling. Sometimes she will answer me and other times she is out of it. I am just looking for some advice as to what could be wrong with her. And if this is the beginning of the end, what else I should expect and for how long. I love my mother but it is very hard to see her this way and take care of her needs all day long. I do have 2 children (pre Teens) that need my attention as well and it is just very hard.