So... in Texas, if the mother is deemed incompetent to make decisions for her/her child's health, who has "power of attorney" over it? The father? If so, why can't he abort if he damn well feels like it? To him, respecting the wishes of the mother may be more important than the birth of his child, especially if said child won't have a mother and may be handicapped.
I know nothing about Texas law, but the quoted lines say that you can't withhold life-saving patients to pregnant patients. Nothing is said about aborting fetuses from pregnant people on life support, then taking them off life support once they are no longer pregnant. I feel the law might have been put in place to protect families without enough money/insurance from losing a WANTED child because some hospital needed the bed for financial reasons.
Also, if the fetus hasn't aborted already, and that no details were given for how long the mother was hypoxic, it's very hard to say what its outcome will be. Could be anywhere from severely handicapped to 100% healthy. You'd need to watch and see later on in the pregnancy for problems.
The argument of mandatory organ donation is dumb. Sure, opt-out systems make a ton of sense and would save a lot of lives, but FORCING people to donate organs is an absurd idea for how much it infringes on your autonomy while alive.
As for "wasted utility" of letting bodies go to "waste", you must consider that the vast majority of people don't see death as a sterile emotionless event, especially when you take religion into account. If a family member dies, but gets the treatment that the rest of the family desires, you keep the survivors that much mentally healthier and more productive to society. Forcibly harvesting dead people might save some lives, but it would come at the cost of pissing off and drastically reducing the productivity of a large number of surviving family members and the people they disrupt as they fight legal battles or grieve longer than necessary.