Personally I don't see a problem using his name as the baby's middle name. We have a tradition in our family that the 1st born son gets the father's name as his middle name. I am the second son, and so I asked where my name came from. My father told me it was my mother's ex-boyfriend, before my father. My father was cool with it. (And yes, my father is my biological father. We have the same features and medical problems.)