First of all it is not a best way to find a BFF (best friend forever) in school or during the childhood because neither you nor your friend have not yet became complete individuals with mature personality. The things, ideas and values that used to unite you, became irrelevant, and it is absolutely normal. Usually we do part with our school friends because it wasnt a way of life, a philosophy, views and interests that united us, it was school or some special classes, or the fact that we lived together or near each other. When you grow up and form you future life position, interests and find you way or at least a path to that way you can finally find a friend that will be the one. After the school a have part with all my school friends because it turned out that actually there was no real friendship between us, yet sometimes we do call Each other or go together to restaurants or wherever, from ten people whom I used to call friends, there are only two left, but even these two are not considered as real friend anymore, and I have completely cut off the relations with others because there was no sense.
When you finish your school this understanding will come without saying and you will understand it not from your mind but first from something deed like subconsciousness. Just take you time. The only question I have is why your friend became so crappy? The thing that he speaks about how he spends his money (probably imaginary) has the only idea - to hurt you, he probably jealous of you now even more than ever, because not only you have an easier life because you are still in school and have more time to live as you wish and the society has no influence on you because you dont have to work to live. But also you probably will go to collage and have a batter life as a result. Not him, so trhis is the only thing he can do for now, soon he will just escape from your friendship.
This is only my opinion, I can be wrong, and probably I am, because I dont know the situation and you.