Hollie will be worse for it, when this all finally ends.
We genuinely don't know that.
It may well be that she finds comfort in the knowledge she did everything she could to prolong his treatment.
Finding her son hanging from the bannisters will have been (and will remain) the worst moment of her existence. I'm sure she has questioned over and over again what she could have done differently. A million "if only" and "what if" thoughts.
If treatment is withdrawn tomorrow then that will be how she can process why he died, not because he tried to commit suicide or a prank gone wrong and Hollie did everything she could to prevent that, even if she couldn't prevent the incident in the first place.
You don't have to agree with her decisions to have some empathy for them.