"Can he force me to sell?"
Yes.
"If so what can i do in order to stop/delay him? "
Buy him out. And since you can't do that, perhaps a good kicking, screaming, tantrum?
Seriously, if you cannot afford to buy him out and he wants to sell, he can compel you. So, rather than wasting time, effort and money ( especially on legal fees), you could reach agreement on when to sell and how to divide the proceeds.
I do not recommend that you bury your head in the sand and refuse to consider the prospect - in the current climate you may not even be able to sell but if you can, it may ( or may not) be at a better price than in a year, or two years..........
mf