My eldest daughter had a daughter with her partner. During the time of her pregnancy and after, there were increasing problems as he was unemployed and depending on alcohol a great deal. Came to a finale when bailiffs starting turning up at the house as he was using it to fund his life=style. With help from us, his part of the house was bought out. He had, actually, never paid much, deposit had come from the sale of flat my Daughter had owned, and he had become unemployed within a year of them moving in.
My D was always determined that their young daughter was entitled to have a relationship with her father. Over the years, he has never paid a penny towards her maintenance and, at first, I was angry that he did not just go away and disappear.
However, as time has gone on I can appreciate how correct my D was. Money is not so important as the fact that my g.daughter knows, and has a good relationship, with her Daddy.
Strangely, each time he has become ill, the first person he has turned to is my daughter - even when he was in a relationship with another woman.
So, over the last ten years it is my D who has made him go to see his GP, get treatment for his different cancers. Even now, when he is being treated with stem cells to counteract the damage done to his body by so much chemo, etc. , it is she he 'phones from the hospital to collect things from his flat (this flat was one my D managed to find for him, when he was desperate to come back to this area). He does have a doting, elderly Mum and a sister living in close proximity.
My D has a responsible, stressful job in the NHS as well as the sole financial, etc. responsibility for her teenage daughter and I do sometimes get upset that he puts so much on her, yet so very proud of her that she feels it is important for their daughter for them to maintain a good relationship. Her professional life definitely spills over to her personal one.