He's mine...

So my sister just got a new boyfriend (not engaged or married). The guy has been in her life for almost a year now. He's great with the kids (I think). She has four kids. Three of the father's are in their lives but he claims the 8 year old who's father isn't really active in his life.

The 8 years old boy's father and I are basically good friends, so I know what's really going on. Every time I go around her boyfriend, he refers to that boy has his son... Making comments such as "where's my son, how's my son doing, etc". When he makes those comments I feel a little awkward. At times I feel a little angry, because I'm sure he wouldn't want nobody claiming his child as theres.

At the same time, I'm kind of happy someone cares enough to take on that responsibility. However, it also seems like they are trying to get that boy to forget about his father, so he can replace him.

What do you guys think?

I am hoping I understood this correctly:

1) your sister has four kids with four different men
2) three of them maintain contact with their kids, but one does not
3) you are "good friends" with the one who does not maintain contact
4) your sister has a new boyfriend who wants to play daddy to the neglected child
5) #4 bothers you

If I have this right, there is a helluva lot more to be worried about than you think. YOur sister has some major issues, but they are for HER to worry about. As for you, why on earth would you want to be "good friends" with someone who would do that to his own child?