Questions about my 15 month old...

Hello, I have a 2 part question here! First off, our 15 month old boy has gotten in the habit of waking up at 12am from his crib.. sometimes sooner. We have not implemented CIO at all, although he’s been able to put himself down several times for naps during the day. So when he wakes up we wait a few minutes to see if he’ll go back down (never does) and we rock him down which leads to a major freak out when we try to place him back in his crib and then bring him in bed with us to nurse and carry out the night.

I’m ok with him in our bed, but I also would like him to be in his room and feel that’s best. I realize when he wakes up he’s expecting to come in our bed now. Any tips on how to get him to stay asleep/ in his crib that doesn’t involve a crazy cio session? Maybe something gentler? If not I might have to bite the bullet and sleep train. 😳

Second question is, our pediatrician said to be careful nursing him off and on all night long because it could rot his teeth. Has anyone had experience with that?? I honestly never thought about that and we brush 1-2 x a day.

Thank you and sorry for the long question!!!