Do you have parents/family nearby? If so get him used to sleeping there during the day then do an over nighter and build from there.

My GS was 19 months when his brother was born and he slept fine at our house. It also made the change over better as he was used to us around. He stayed with us until the baby came home and I visited often over the next few days, even though his dad was there, just to spent time with him.

Not sure if you have the option that bronners suggested. It will also depend on how you feel afterwards.