Last name

Last nameCategory: ReligionLast name
Maria asked 3 years ago

as Salam wa alikum.. 
We are 4 sisters and found half my big brother 11 years ago (his mum took my big brother away from my dad) but alhamdulillah with the will of Allah we found him.. he used to live a Christian life but reverted to our deen alhamdulillah a few months after we found him. He has been blessed with a son but he will not give his son my fathers last name, instead he opted for the his old Christian last name, his excuse is that that he will be luckier getting a job with a Christian last name rather then Arabic. We know that kizmat is in Allahs hands alhamdulillah. I am now pregnant again, all praises be to Allah.. I have my first born and have given him his father last name but I was wondering if it would be haram for Me and my husband to give the next son my fathers last name. Jazakallah