This is a question that's more reliant on personalities and behavior than on the law itself. Kicking him out doesn't relieve his parents of their parental rights. If they decide to complain, the police will be sympathetic to them initially.
This is not like a custody case, in which a child's opinion carries greater weight with a judge at 14, and the police generally don't take a non-intervention approach until the minor is 17. Your position is stronger if you're a relative -- if not, this is somewhat risky. Further, if the minor wants to further his education in school, you'll need legal documents right now to be able to enroll him. I don't know which state you are from, but school enrollment laws are not uniform across the country so I can't advise you of the situation there, but until he's lived in that state 6 months and is at least 16, he may not be able to enroll without consent from the family or the intervention of Children's Services in the state you live in.
Frankly, at 16 this is unfortunately a potential Children's Services issue even in Pennsylvania. Technically he's a homeless child. You really should consult an attorney.
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