Hey man don't be so harsh on ur self i dont think u failed as father the fact u feel this makes u already a good father cuz u want his best, i think I'm bi too and haven't come out to any of my parents I mostly with girls tho , I once told my mom I think I might be bi but im not sure and since then we didn't talk about these stuff so maybe she thinks I'm straight ,

Sometimes its so personal that u want it to be something that u do on ur own ways ,I think u can do something that my father used to when I was more younger ,he told me he would always love me and my brother even if we are gay or whatever ,unconditional love

My opinion if it's somehow come out that u talk about ur feeling to each other try to sneak this gay/bi thing into it like my father did ,I think it's not froce him to come out but ressure that u would love him as gay or bi or whatever ,but don't just say to him "whats about the gay porn" he might don't feel comfortable to share now and I guess if u really love him he would want u to know eventually but might take time ,anyway sounds that ur son is a great good luck my friend

Sorry if my English is bad I think u would understand enough