I expect Clarrett really is upset about his friend dying, but is lashing out at the nearest target.
As for why he can't go home, I expect NCAA regulations prohibit anyone outside his family from paying for the tickets...and his family can't afford it...but only half of that got stated.
I read somewhere that he would have to pay for his own plane ticket. NCAA rules prohibit OSU from doing it. However, later he could petition the NCAA for a special case refund.