Can't decide if I'm being unreasonable and a bit precious or not. I'm in my thirties with young kids and a job. Parents live reasonably locally (1.15 drive approx) I have a sibling a few years younger who is also married and I have a good relationship with, no issues there. The problem is with my DSIS who was born when I was a teen and mum was in her mid-forties. We got on fine when she was little and I honestly don't remember being jealous at all in fact used to babysit and pick her up from childcare although I wouldn't say I felt this was excessive. Then I moved away to university and tbh probably didn't think about her a great deal a bit too preoccupied with my own stuff.
She was a fairly unpleasant teen from the outside very moody and sometimes really nasty to my parents. She did well at school though and seemed to save the worst of her behaviour for the family. Parents have always babied her and I have resented this. Example while I used to have fights with my mother about helping around the house (the fact that I didn't do enough) DSIS has never been expected to lift a finger. Mum waited on her hand and foot until she left home. Maybe she'd just got more realistic about teenagers.
Fast forward a few years and DSIS is an adult away at university studying for the same career as me. She phones mum constantly and seems to require lots of emotional and practical support; for example driving 3 hours to where she is at uni quite a few times to take her out for lunch because she is finding things tricky. She phones mum constantly and moans about how difficult she is finding it. When at home after exams mum runs around after and waits on her hand and foot as she mostly sits in her room watching netflix. Recently she had exams and I snapped at my mum because she was telling me how worried DSIS was about the exams and I just got completely fed up with hearing about her. She also has never had a paying job yet manages to go long haul holidays twice this year. I did a fair amount of travelling during uni time but was also constantly doing low paid work to pay for it, sometimes to the detriment of my grades so I know they give her significantly more money than I had at university.
I just feel a bit fed up. I did some more professional exams 2 years ago when I had a 2 year old. I don't like to make a big deal of things but my parents knew I was doing them and still never asked or offered to help with babysitting so I could study or anything. Now I'm asked to be super sympathetic at another set of DSIS uni exams (not finals or anything and the career we both do has lots of exams to do) They do help with childcare but mostly if asked. My mums someone who loves babies and I always thought she would be really into grandchildren but although she spends time with my 2 and will babysit if asked I feel her heart isn't totally in it.
I don't really know what to do though as I also think my parents (now in their 60's) are tired from dealing with all this and probably don't need me giving them more emotional angst. At the same time I feel it's going to affect my relationship with DSIS as I see them constantly still dancing around her. I appreciate that although DSIS is technically an adult she is still very young (21) so maybe I ought to cut them and her some slack and be the proper adult. I think what I'd really like is for them to not place her quite so much at the centre of everything but to spend more time with their grandchildren. AIBU to speak to them about this?