Scifi father figure farmer set on earth

At least the beginning is set on Earth. There's some kind of low orbit recruiting outpost. The main character comes from a failing farm with an alcoholic father. He goes to find work on a farm down the road where the elderly farmer and his wife (I think) feed the boy extra and end up becoming something like adoptive parents. The main character is 17/18 and I think the old man is veteran of some space side military. I think eventually there is a confrontation between the abusive birth father and the farmer. I can't remember much after that. I'll update with any details i remember down the line.