You can't save the world, or all the bees for that matter. :-D
I think you're being way to tough on yourself...You can lead a horse to water, but you can't make it drink.
Growing up, my older brother would always end any advice he may offer with the following statement, "Now that my friend is good advice, now what you choose to do with it, is up to you".
I would suggest you take the same approach with your buddy and not take it personal, he'll either figure it out, or he won't.
Good Luck! :)