As a player with a lot of tournament background, I'd feel very comfortable playing in a game like this.
I know you haven't called a push yet, but you need to do your best to put him on a range. Hand values fluctuate a lot based on what he is pushing. Against any ace, any pair, JTs is way better than A6o, although both are folds. Against any two cards, JTs and A6o are both similar and both calls.
Anyways, just consult a chart
like this, or if you want to play with the range yourself, download a program
like this, which you probably already have, or buy
SNGPT, which is made for tournaments, but would be able to solve this problem very easily (if you can put the pusher on a range).