My husband of 3 years decides he wants to go back home to El Salvador, I was born here but my mom is from?

germany, I have a previous kid from a previous marrige and my sons father is part of my kids life every week, I can't take him away from his dad, I am really in love ! I have no idea what to do?? I can't help my mom or son with that type of money over there?? My husbands mom is really sick and he wants to stay there to take care of her.