Two ghosts had a baby but i cant find it

Ok so I had two elders and their kid as a family and the parents have been dead for a little while now; The mother had a baby somehow with another ghost that wasn't her husband and according to the family tree he should be alive since he doesn't have the ghost look but I can't find him through the adoption option on the computer or anywhere.

Is there a way to find the baby? Like a cheat to force him into my household or what?