Oh no. Believe me, parents will force it.I agree, if he wrote 5 symphonies then it must mean he enjoys doing it, or else he just wouldn't do it.
Even if adults were behind him, "pushing him" to do this kind of stuff, a normal child who enjoys playing football still wouldn't do it.
And no, writing 5 symphonies isn't that big of a deal. Are they any good? I doubt it a lot. It sounds more as though a guy has a decent composition student who happens to be 12 and this means "HOLY CRAP, CHILD PRODIGY!" The Julliard guy then uses his ridiculous influence to get the stuff played. This happens constantly in the music world--get a really good student or at least one who is notable in some way, who is probably really good or notable entirely without your influence, and then use them to drastically increase your success and fame. This child prodigy nonsense springs up every year or so in the music world. It's all bunk.
Oh, and Mozart wasn't an alcoholic. Plenty of other composers were, Mozart wasn't. He just kinda died and nobody's entirely sure why.