Since you have so much time, I think trickling him information over the internet would be your most effective approach. He probably doesn't have time to read an entire book on the subject, so you start compiling a list of pros and cons and start feeding the list to him slowly. I say provide any cons so that you can address them or refute them. We get affirmation on here almost daily that we are doing the right thing. Members share stories that remind us why we homeschool. You can start with Amie's post about Standardized testing in a public school--that ought to open his mind a bit when he thinks about the possibility of his child being denied food, drink and exercise during 4 1/2 testing period!
I remember when Beau was tiny and we had JUST had Patryk and I really wanted to homeschool, but DH wasn't 100% on board, and right out of the blue we were watching Glenn Beck (I love that man) and he said "Sell your car, get rid of your cable, find SOME WAY to homeschool your children to preserve this country." DH said, right then, "Let's do it. I don't care what we have to do, let's do it." LOL I guess Glenn is responsible for our homeschooling now! lol
I have never met a snooty hser, but I have met a few snooty young gals at the Christian school Jeannie attends. Thankfully, it has let up for the most part.