One of my friends is like this now and we are late 30s... her mum and dad pay her mortgage, she has never bought her own car, she will not drive anywhere new alone - her dad (in his 70s) has to go with her, so she will only drive to work, her parents’, siblings and the local park and shop. When we were at uni together she was constantly running stuff by her mum and dad - she even called them the first time she paid for something using her debit card.
She is trained in a highly skilled profession but is working a low paid version of what she should be doing because it’s easy to dive to, jobs with her full earning potential are in cities and the travel scares her. She’s missing out on earning about another £30k.
Her husband is a lazy, alcoholic sponger, but she needs to be in a relationship. Her mum even bought her engagement ring.
Her parents are lovely and they’ve raised 3 older siblings who are all independent and self supporting, I think they’re in a similar position as you in that they feel they have to help as she harangues them.
My mum and dad are very supportive and loving. Financially they did many generous things when I was younger - paid for driving lessons, bought me a car, matched savings to help - but all of these gestures were about independence. At home we were responsible for cooking for ourselves and doing our own washing and ironing from being 16, encouraged to get jobs so we could have mobile phones/petrol etc. I know my family are there for me but I’m proud to be independent. It sounds like she’s got self esteem issues.
I’d have a frank conversation with her and tell her this is having a big impact on you, that you are concerned for her and her future and you love her to bits but you won’t be around forever to sort things out. She needs to help herself and stop quitting stuff. I’d pull financial support, unless it was a genuine emergency. Stop with the lifts etc. She’ll probably fall out with you, but do you want her still doing this at nearly 40?