I've just been reading through these comments and have been trying to get my brain to put together the thoughts of what I'm feeling to properly articulate what I want to say. You're pretty much there, where I want to be.
Not that I think that mom is over thinking the "gay" thing, because she is doing god's work with her son, but I am also hoping she doesn't forget about raising a smart kid with a life ahead that doesn't involve small town homophobia (that, unfortunately, is a byproduct of their environment and her being such a caring mother, and being so enlightened!). But, in the end and hopefully before I'm dead, talking about sexuality will only be nuances of hetero- and homosexuality.
What lies ahead for her son is maneuvering through life in general. Stereotypes exist. He could be red headed. Blond. Left handed. Short. Tall. Support groups (unrelated to my previous examples) exist for people that don't have support. He obviously has support. Let's raise an intelligent and successful and proudly out human! Mom's support and life wisdom is what needs to win here.
I'm not mad at the suggestions that have been put forward in this thread, but they mainly seem like projections and study-based that don't apply to her son. Let's stop making homosexuality a problem and start talking about it like its just a human trait. I mean, I don't know if I live in a neighborhood that Whole Foods decided to open up in because we like what Whole Foods sells or if I moved to this neighborhood because I knew people lived here that like the same things I like. And, yeah, those are mutually exclusive because I lived here for 15 years before WF moved in. I guess (in a weird way that I don't feel like un-typing) what I'm saying is that preferences in life exist. And, to a markerter's delight they can fit us into a neat lil box, but at the end of the day we will hopefully soon just be a demographic.
Mom - Keep doing what you do as a parent, not so much as a parent of a gay kid. Of course, your community will dictate differently and might even cause some problems, but your gay son is no different than a socially awkward left-handed redhead going through their teen years.
Us homos are out here. Some of us survived life without reddit and without a supportive family. And we are smart, successful, good citizens. You might not recognize us because homosexuality is only one part of us, not the whole.
Besides that, everything else here (though, I haven't read it all and know some of the AskGaybros guys can be a lil offbase. And weird.), is great advice. Here's what I wish I would have been taught (and it can be applied to any gender/sexuality): sex isn't always great, humans can be assholes, STIs exist, hangovers suck, drugs can be addictive, always have in savings at least three months of living expenses in case you are out of work, know that certain Masters degrees do not pay themselves back, love can suck but sometimes really fucking amazing!
Cc: /u/feralsethos