it is very hard to do taht, but sometimes there are not many more options. Your mother doesn't sound liek she can do it on her own any more, and while she might not be happy to consider the alternatives, there doesn't really sound like a choice.
If finances are good have you thought about getting a live in carer to help them both once you mum comes home?
be warned though, they are not always trained, and not cheap (i was getting paid £70 per day 3 years ago + agency fees and the cost of an exta person living in the house).
Sandi