Toddler sleep advice

Hi everyone, I’m having trouble with my toddler’s sleeping habits. Ever since having a new baby my 4yo son has been extra clingy and he refuses to go to bed in his own room. He has to fall asleep in our bed holding my hand, then my husband picks him up and moves him to his own bed once he’s asleep. Every night sometime between 2am-5am he wakes up and crawls back into our bed. Every once in a while he will actually fall asleep in his own bed, but then he still crawls in with us when he wakes up. How can we break this habit? He was always a good sleeper as a baby and has been sleeping in his own room since he was 8 weeks old, but this bad sleeping situation started when I was heavily pregnant and has gotten worse since having the new baby 3 months ago.