Is this a known personality type...? At least two people I've know have been like this.
They are fantastic when the chips are down. Checking in, stream of encouraging texts etc. But when you're back on form, they are not interested at all and drop you like a sack of spuds. It's like you are a pet project.
One of them regularly visited a former colleague who was an alcoholic. Took her food parcels, books, had a chat. I thought "what an absolute dismond"...then I sat beside her at work. She would report back on the colleague in a horrible way, doing an impression, telling me what a mess she was, rolling her eyes about her. It's like she loved the "doing good" and despised the person.
Another was amazing when my relationship broke down in spectacular fashion. But I've noticed she quite liked that dynamic, now my life is steady and happy, she's a different person.
My armchair psychology is wondering if there's a weird power play with people like this. They thrive on an almost parent/child relationship and get resentful when it becomes more balanced. It's made me very cynical!