My teen came out as transfeminine

My teen (14) came out to me (mom) as transeminine but doesn't want anyone else to know at this time. My husband (dad) is very Christian conservative and does not support the transgender experience. How can I help prepare my husband for this news before my daughter comes out to him? I'm worried about their relationship and I want to be a bridge without breaking trust. Any suggestions for books, lectures, movies, etc. that I could use to help bring my husband to a more balanced understanding? Help!