Crib question

Ok. I have a son who will be 1 in October and I'm due with another boy in November.

I personally think we need to buy another crib but my boyfriend is convinced that it's pointless since the newborn will most likely sleep with us the first 6 months like our first son did and he thinks our first son will not need to be in his crib much longer after that point. I personally don't know since this is my first time with everything obviously. BUT I think we should get a crib anyway since our son's crib is a 4-in-1 and he will be able to use it for a while if we choose to and the new baby could do the same.

Suggestions or advice?