I would start by listing out what it is that your family wants for said child (if I'm being hypothetical about it, whether I'd be this disciplined in reality, well, working on that atm myself). Then rate each option/potential option against each factor... of course you're going to have to make some assumptions, so additional research is probably needed.
The other things to consider are what the options are for each choice if they don't wind up working out (ex. private current school, terrible teacher, can you get out of the contract? public school, turns out that your child is out of range for the class and they won't work with you to accommodate him -- can you then reenroll in the private school? etc.)
