Need your opinion on something...

Dead_Darling

Ok, here's the background behind the story:

My friend has a daughter (4 years old) from a previous relationship, and the two broke up just before his daughter was born. Anyway, since then my friend's been looking after his daughter every weekend because he works full time during the week and the mother works part time. Her mum met someone a couple of years ago and now they're living together.

Over the weekend, the daughter told her dad that her mum's encouraging her to call her boyfriend 'dad', which obviously didn't go down well with my friend. He had a massive argument with the mum and asking why would their daughter need to call both the biological father and her boyfriend 'dad' - the poor child's going to be confused! My friend's tries to be the best father he can be when he has his daughter over and lets her be a kid. When she's at her mum's, no one really seems to look after her.

I feel bad for my friend because his daughter is his life and wants only what's best for her; I've never been in this situation so I don't know what to say to him to help him through this

All opinions will be helpful