Isn't this wrong?

ok so my older brother was married to his wife(Edith) for 5year and he cheated on her with a lady named Marla. He had 2 kids with Edith, their names are Raymond James Jr, and Brianne Marie (after my mother) so now he is married to Marla and she is pregnant and she doesn't know the gender, but she says if she has a boy she is going to name him Ray Santiago (which in the bible it's the same as James) and if she has a girl she wants to name her Brianna Marina. Isn't this totally wrong? and i told Edith about it and she got sad about it because my brother is totally ok with Marla naming the kid that. it's like she's trying to replace his family which is totally wrong. and my brother just tells "oh alison this is none of your business" when i tell him it's totally wrong if she's going to name the baby that. there's a gazillion names out in the world isn't totally wrong for her to do that and for my brother to be ok with it?