That is the situation my husband is in right now. He does HVAC and all manners of contracting/construction work. He has eleven more years to go before his youngest child of 3 reaches 21 (it's 21 in NY not 18) and most likely he'll have to continue to pay for their college. He's 45 now and feeling his age. I do computer repair/desktop support. We already have gone "galt" in the fact that we have a house in the country (sadly on a "wetland") use a well, septic system, burn wood exclusively for heat, never eat out (that includes take out and pizza), never go on vacations. I make my own bread, yogurt, creme fraiche (sour creme) and am thinking of getting a goat. We both work 40+ hours a week and have to "go galt" because he brings home next to nothing after child support and taxes.
I also have a 30 x 30 raised bed veg garden and fruit trees and bushes, do canning, drying and freezing.
I feel bad for your husband. My only advice would be for him to work out everyday and stay in shape. He does not have the luxury of letting himself go.