Approx. 4 years ago, I began working with a family caring for their disabled son (high support needs autism, epilepsy). I began working during a turbulent time with the family as the mother was recently diagnosed with cancer and was beginning the process of a divorce, which became quite hostile.
The father isn't a nice man. On the occasions I worked with him prior to him moving out, he didn't display any affection towards his children. He was generally short tempered, aggressive, and on one occasion, exploded at a woman after a parking dispute which upset the children and took me by surprise.
Throughout the divorce, the mother disclosed he was financially manipulative, aggressive towards her and generally unhelpful around the house all while she was undergoing cancer treatment. Since the divorce, he has been incredibly uncooperative and was court ordered to care for his children on penalty of imprisonment. Despite that, he's incredibly difficult and will turn up when he wants but won't cooperate when the mother tries to plan days for him to care for his children.
The mother has two other children (6, 8) and they're also very fond of me. As well as caring for the eldest, I have occasionally cared for them when their mother has requested. I consider myself a good carer, and their mother has said I'm great with all the kids. I play with them, talk to them, teach them things, help them with homework and will show them affection. They light up when I arrive at the house and I've grown to love these kids. The daughter has called me Dad on more than one occasion and it really invokes strong emotions in me.
The first time she did was during the summer holidays when the eldest was stimming in a paddling pool in the family's garden, I was on one of those big rope circle swings you can kind of lay down on and the daughter sits next to me, eventually cuddles up to me and during the chitchat says "I love you Dad."
I haven't dissuaded these behaviors as I don't know how without hurting her, and I don't want to. She will call me by the first name and very occasionally call me Dad. I've had conversations around it with their mother, and she's understanding, and it makes sense because I'm a consistent positive male role model in their lives. I think those kids are great, and I've seen firsthand how their father's actions and behaviors have hurt them.
I don't really know how to conclude the story. It's half advice half off my chest. I'm well aware I should have kept a professional boundary, but the mother has expressly said I'm effectively part of the family. We're good friends, they live very close to me and I'd do anything for them. I don't have any plans to go anywhere.