D.B.
You are very open to your own struggles to accept him because he doesn't conform to what you and many others consider "normal." Your honesty is refreshing. There may be others in the family and the social circle who will struggle but may not be as hard line as you think. Maybe they are anti-gay because they think it's an abomination, and maybe they are anti-gay because they just don't think they know anyone who is. And when I say "gay," I include bi, trans, fluid and all other people who face discrimination.
It's one thing to be concerned at what our gender non-conforming kids will face. It's another to "freak out" and feel that everything "sucks" - so I think you need a lot of support and help for yourself to be able to be more comfortable. As your child enters puberty, his awakening hormones and desires will put more challenges in front of him. He's going to need you to be a lot more calm and relaxed than you are now.
I think you should reconsider using terms like "effeminate" - I know what you mean, but it puts a judgment on actions and mannerisms that reinforces the very stereotypes you oppose. We have lots of kids, teens and adults who exhibit a variety of behaviors and which don't necessarily line up with their sexual orientation and gender identity.
Mr. Rogers famously told a child worried about bad things to "look for the helpers." So I think it would help you - perhaps with the help of a counselor or a PFLAG group - to look for all the gay people who are "out" and strong and so much happier than they were when they were closeted. Start with Ellen Degeneres, not just for her personal story and the role model she has become, but for all the people she has encouraged and welcomed and supported on her show, from celebrities to rising stars to ordinary humans. Watch her shows and segments on youtube or On Demand, whatever you have. Just this week, she featured Jesse Tyler Ferguson, Kalen Allen, a, to some extent, your sense of desperation and panic.nd a young football player. Three different gay men with totally different mannerisms.There are hundreds of other examples.
You are trying to do this alone, which is increasing your sense of isolation and desperation. You need to give your son the sense that there is support for him - and that means finding support for yourself.
Whatever other people (grandparents, friends, the general public), your son needs to be raised with strength and resilience and self-acceptance. You are panicking before there is definite rejection from family. If they do, he needs to have the strength to get past it.