This is a very difficult situation…
My 17 (almost 18 year old daughter’s boyfriend is not Baptized) and we were discussing it one day. He asked me if anyone could Baptize him and I said, “I don’t know. ” I looked it up in the Catechism and sure enough, anyone can Baptize you it says so in the Catechism. Well, I might get tons of opposition to saying this… but if I was the mom, since the Catechism says so… I would get some Holy Water and Baptize Asher myself. Your husband is keeping him from receiving this Grace just because he doesn’t want to make promises…which is the wrong reason. The other thing, which would probably be a lot better is to take him to the Priest or Deacon and just ask one of them to Baptize him. There would not be a ceremony, so no promises from your husband would have to be made. I have a friend who Baptized her Granddaughter… the mom and dad did not come… they aren’t Catholic, but the Grandmother was very concerned about the 3 or 4 year old receiving this Sacrament.
Another thought, did you know that the Catholic Church recognizes Baptism that is done at any church. Your son would not have to be re-Baptised.
About having your husband’s anti-Catholic friend as a Godparent… I would definitely so NO to that idea. It’s hard enough to find Godparents that do anything even when they are Catholic! You really need someone to pray for your son and give him support in carrying on the Catholic Faith… not talking him out of it. I would forget the Godparent idea just so you could get him Baptized… look ahead to Confirmation Sponsor or RCIA sponsor as a Godparent… this will give you more time. Also, if you have a close Catholic friend, ask them to be the “adopted Godparent”. Just do spiritual nice things for the Child… but nothing official.
Hope some of these ideas work for you …. at least maybe they will help to give you some ideas…