How to tell a 12 year old his father passed away some years ago?

This is not for me its for a relative, she has a 12 year old son who she has been having trouble with his schooling. Basically he is acting out and doesn't want to do any of the work.The situation is that the father passed away a few years ago, he was involved with cartel people and they killed him. After the incident the mom left Mexico and moved her to the states and the son enrolled in school.The 12 year old boy does not know about the status of his father, and when he and his mom argue he always says he is going back to his dads auto shop because he knows his dad will show up, wants to go live with his dad etc.My personal opinion is its better for the son to find out now than later, but the mom thinks it could backfire and cause him to act out more.I guess its basically a mix of the father being gone and being in a new school where he isn't fully on level with other students due to he was going to school in mexico.She has been taking him to a therapist but the boy pretty much tells her "this isn't going to work on me" so he assumingly goes in with a negative reaction. He tells the mom and the therapist he is doing good in school etc but the teacehrs are the ones who say he doesn't want to do any of the work.Any advice would be appreciated. via /r/Parenting http://ift.tt/2oyLFxs