No, laws between states are much different.
In your daughters case (as opposed to the news story you found) was the old lady could not have helped herself at all. she was on the floor, could not move, her call for help, was her literal call for help.
your daughter 1. took an alleged overdose. 2. told her husband not to let her die then she 3. got up, went to bed, where she died.
you cannot prove husband knew anything, you cannot prove he believed her, knew she was going to die, watched or administered the fatal dose. you just cant prove anything other then she in fact died.
Your daughter had the duty to protect herself because she could. she could have called 911. instead of going to bed, she could have gone to the phone. her call for help, would have been a phone call to 911.