If he loves her so much...
why has he been living with another woman (who happens to be pregnant with their second child)? If he wants to divorse his comatose wife to marry his girlfriend, that's one thing. A divorce might free him of future medical expenses, too, but that would depend on the nature of the settlement. Only, he wouldn't be able to get the remainder of the $750,000 malpractice settlement if he divorces his wife, would he? But if she dies, he gets the money. His decision may be motivated by love, but perhaps not for his wife.