V.W.
Hi S.. I would just put the mattress on the floor. That's not a big deal. Believe me, he won't be the first toddler to sleep on a mattress lying on the floor. Lots of families transition that way. My son wouldn't sleep in his "convertible" toddler bed either. We put his mattress on the floor. When he was a little older we put a twin bed in his room and pushed it up against the walls (side of bed against one wall, head of the bed against the perpendicular wall) and used a bed rail on the other side. As far as him waking up, there could be a lot of reasons or issues to address. There really isn't enough information in your original post to help with that.