J.K.
My son got an abcess on a baby tooth when he was about 5 or6 and his pediatric dentist said they could do a root canal but that it was a baby tooth and he would lose it anyway so they just pulled it and put in a spacer to keep the other teeth from growing closer together. I would say it would be a waste of time, money, to have the root canal and pretty traumatic for a 5 yr old. Pulling it would be a better solution. Good Luck!