My brother is in love with fathers love child?

I first commend you & your whole family for doing what most folks wouldn't even consider doing. After finding out what you all did, you were so kind to open your hearts to her, & especially your mother! You do have one special family for sure! I'm sorry to hear about your brother's feelings tho. He must consider her as almost the same as yourself - in a way. Possibly if it's really affecting him in a negative way & tearing him apart, counseling just may be the answer. I've been to several counselors in my life time & they DO help. If nothing else helps, you feel it is overly affecting him, I would highly suggest he seek help from a professional. I'm sure it will help him...the very best to you all...:)