You've got to go for it and find out for both of your sakes. If you're attracted to him and holding back out of fear of what you might lose, I promise you will regret not taking the chance later in life. And if you don't hold back then one of either two things will happen - it will work out and you will become closer, stronger, and happier, or it won't. If it doesn't and it affects your friendship, then your friendship isn't as strong as you think to begin with... but if you are good, true, kind people who care for one another, then even a separation won't break your friendship up.