I'm sad that my paragraph about not loving my mother has resonated with so many people, but I also find it immensely reassuring.
@Lighthouse, I understand about the alternating between feeling like a terrible person and feeling nauseous. All I will say is, if they do try and send him home, get Occupational Therapy involved to assess him and see if he needs help at home, don't offer to help out, and don't let your Mum say she'll do whatever needs doing. The help is out there, but in my experience if you give them the slightest whiff of being prepared to take it on, they'll pounce on it, and that's not fair or sustainable.
I still have to give myself a good talking to to unpick whether I should visit Mum because I want to or because I feel I ought to - I visited yesterday, as a matter of fact. She greeted me by asking if DB was with me and asked me about four times in the course of my visit when he was due back. This is par for the course, though - a couple of years ago when she was still at home with carers I had to spend three weeks there while DB went away on holiday. I thought I did ok, and every day she would tell me to go out for a while (I did some days); when DB came back she had a good old moan about how I kept going out and I didn't look after her properly...
Anyway, I'm picking DB up from the airport in a couple of days. He still doesn't know about his pet because he hasn't been in touch, and as he didn't want to know if anything happened to Mum I guessed he wouldn't want to hear about that either.
As for going NC with him not making much difference; I hardly hear from him now unless he wants something, so it'll pretty much be business as usual.
Chin up, everyone. This too shall end.