I would like some perspective here and welcome all viewpoints as I'm not sure what to make of this situation.
Dsis is 45 and lives with DM. It's just the 2 of them at home as the rest of the siblings have moved out over the years and DF passed a way a few years back.
Dsis has OCD. She takes meds for this and has NHS cbt sessions on and off over the years. She works part time as working anymore gets her stressed and worsens the OCD. Any life stress worsens it.
Over the years, in my mind things have become worse in the sense of the relationship dynamic between them. DM plans her entire life around dsis. She does all the cleaning and cooking in the house. She cleans up after her, does the washing, everything. DM says she does this to keep her symptoms at bay. e.g she washes her hands often so she doesn't let dsis do the washing up so this results in dsis leaving her dirty plates etc on the table for DM to clean up etc. DM almost treats her like a young child i.e she gets worried about her if she is home 15 minutes late from work, she has the dinner ready for on time as she knows she'll be hungry when she gets in, she'll rush back home if she's out and dsis is coming home. Dsis doesn't think there's anything wrong in being treated like this and think it's 'cute' that DM cares for her so much.
DM doesn't seem to have any boundaries with her and dsis treats and speaks to her horribly. Dsis can be very volatile with the rest of us and generally is pretty difficult. She isn't like this 24/7 obviously but she does seem to have runs in with those around her. DM always seems to take on her point of view and can't seem to think for herself anymore.
It all came to ahead recently when my other dsis had a relationship breakdown and became homeless. There's plenty of space in DM's home and she refused her and her child to stay with her during this dire situation as she stated that dsis wouldn't like it and it would stress her out. I know she does have a right to refuse. Homeless dsis was extremely hurt by this. She ended up staying with us in our already crowded home before a friend gave her a spare bedroom for awhile.
I find the whole thing really frustrating and not sure what is going on with the both of them. Do they have a dysfunctional relationship or is this normal in people with mental health issues?