I'm working on an outline for my new WIP. In it, you have two families that often show supernatural abilities. The MC is psychic. She finds out from a ghost that another young psychic, a 10 year old boy, is in trouble. The boy could be related to either family. No mother or father would be in the picture and it's possible that his closest relative could be a distant cousin. My question would be how long could it take before, with DNA testing, that they find out which family he belongs to.

Is it possible that it wouldn't show if there's no direct family member there?