Stephen Hawking lived over 5 decades of his life incapacitated.
Unable to live, or even move, without the aid of humans and machines.
He cursed God every day of his life, yet I didn't know of a single Christian who said he should be starved to death because his "quality of life" was insufficient.
I've confronted the eugenicists with this question, and not a single one has given me a satisfactory answer.
What exactly, is your question?
“Why didn’t someone ever suggest that Stephen Hawking be denied food and water, thus allowing him to die vs live in such a handicapped state?”
If that is your question, I suppose the easy answer is that unless Stephen himself brought up such an option, perhaps no one wanted to broach the topic. No one wished to be the bringer of such a negative, bleak concept. We have no proof that this was not brought up for discussion, by a Christian or agnostic, however inadvertently.