Can I make my dad go in a nursing home if he doesn't want to?

My dad is 82 and recently diagnosed with advanced throat cancer. Because of his health problems there is nothing they can do. He has COPD, emphysema, heart disease, vascular disease, scoliosis, neuropathy in feet and hands, early stages of dementia,and more. (I just can't think right now but you get the idea). He is also an alcoholic. He drinks a 40 oz beer every day. He stays in his riding chair almost all of the time. He can't walk alone and it's very difficult just to help him the 3 feet he has to walk to the bathroom (his chair won't fit into the bathroom). My mom is 76 and has health issues of her own (2 major surgeries on her legs because of vascular disease this year). She tries to take care of him but he still falls at least 1 a week. I have talked to her and told her this just can't continue. She is killing herself trying to take care of him. She has really gone down hill. I have done everything I can to help them. I got help for them for 6 hours a day but can't get anymore help then that. (Can't afford it). My dad won't let them bathe him completely, mom has to wash his bottom. Just doing that wears her out to the point she is short of breath. He is a very selfish man, he doesn't give her a moments rest. Every time she sits down he yells that he needs something (even when the helpers are there) and doesn't want anyone but her doing it. He can't go to the bathroom alone, mom has to hold it and wipe him. He can't barely feed himself. (Oh yeah he is blind in one eye and almost blind in the other, muscular degeneration). I have 5 siblings that don't really help, just every once in a while. I take them to all the doctor appointments and do all the shopping. I need to go back to work for my own family but can't because of all of this. Luckily I have a very understanding husband and we are making do. There is no POA or anything. I have tried to get it but can't. I don't have the time or money to file for guardianship. I have thought about calling adult protective services because I don't know what they will do. One sibling believes they will do nothing because it's my moms choice to live that way and another believes that will take him and put him anywhere they please. I have talked to my mom about this and begged her to put him somewhere instead of them doing it cause god knows where they would put him. If she does it then I think we would have some control over where he would go.
So I guess my question is: What can I do to make him go into a nursing home where he can get the full time care that he needs?
(Looking at the topics, this fits so many of them)