CIO method

So I'm trying the cio method my son is 15 months I put him in his crib and lay him down as soon as I walk away he gets up and cries he won't lay down at all.. last night I tried it for the first time he cried for a 1 hour and 15 minutes I checked in on him a few time but that made it worse.. when he finally fell asleep he was sitting down slouched over. Will this work if he won't lay down?