I'm currently in your GF's situation (mom was diagnosed with Alzheimer's 8y ago, and she is currently in a very bad condition staying in a nursing home). Depending on my sis and my schedule I visit her 1 to 3 times a week. When I get home after a visit (typically 6pm) I don't feel like doing anything, don't feel like cooking, ... so if someone invites me over for dinner on those days that is a huge comfort.

It might sound strange but I got used to this situation since she has been in the nursing home for nearly 2 years now. Somehow it has become a routine over time. Which means that most of the time I feel/act normal just like everyone else. But then out of nowhere something triggers a memory. That can be a song on the radio in the supermarket, or some of her old friends I run into, ... can be anything. And that just destroys me for a good 10-30 minutes. I don't want to talk about it, I just want to be left alone. I'm a 36y old dude, but during those moments it's damn hard not to cry. But on the other hand it doesn't feel good either if people are deliberately being careful with me.

It's complicated, but for me I just want people to act normal and when I have a bad time I just want my GF (or anyone) to be there without getting pressured into explaining what is wrong. But then again, one moment I want my GF really close to me, but in another moment I just want to be alone.

What I find very comforting is when I know that I can be reached in case of an emergency i.e. that wherever I am at a particular moment, someone in my proximity his/her phonenumber is known by my family in case they need to reach me. Maybe that's something you could offer her.

This does not apply to my situation since I can walk to the nursing home, but if it's a long drive you could offer her to drive her, don't go inside and just pick her up whenever she calls you. Having 'company' on the drive back home is something I'd definitely would appreciate.