Although "troops" means soldiers, I don't think the context has anything to do with the military. Then, the "troops" means a reinforcement to support him?

Native speaker’s answer
Rebecca
Yes, "rally the troops" is a phrase of encouragement that originated from the military! Your guess is right, in this case he's referring to his family, who he considers to be his supporters. Ex: We have an important business meeting, let's rally the troops. Ex: Rally the troops! The game is about to begin.