Her parents have supposedly told her husband, several times over, that if he wanted to give up caring for her, they'd gladly take over that responsibility and he wouldn't have to do anything for her ever again. He won't take the offer.

Also, according to http://www.terrisfight.org, the reason "Terri can't get a divorce" is because her husband is her legal guardian, therefore she can't do anything unless he allows it.

Ugh.