I've read that men can lactate - and have. So even if just a man were left to raise a child, he could begin to feed it. I don't know for a fact that it is true, but I did read it.
On the other hand... my aunt wanted to breastfeed her second child but the child was all colicky and apparently was allergic to mother's milk (or something was wrong, anyway). So they decided to feed it soy formula.
I'm sorry this is the situation, I suppose that child will have many health problems.
But I think that it is something very wrong with the mother and her diet, for her milk to not be good for the baby. I do know that both parents eat a lot of artificial sweeteners, and a SAD diet. Couldn't find many things in their kitchen that I would actually consider healthy.