I have a half brother and might be meeting him soon what do u call his mother (not related to me) or does she not have a relative name
If you and your half brother share the same father you call his mother Mrs. Smith or whatever her last name is. You have absolutely no relationship to her.
If you and your half brother share the same mother you call his father Mr. Smith or whatever his last name is.
You have absolutely no relationship to him.
Just because you are half brothers understand you are still strangers and have to get to know each other. The possibility exists that you might be very alike and get along great. The possibility also exists that you may be very different and can't stand each other. So take it slow.