My answer is along these lines:
We know that values are subjective. But when someone does something we can reasonably assume is likely against their deeper and demonstrated values, then I’d say we should be able to at least force someone a little bit so that we can get to the bottom of the situation. i.e. to find out if there is a temporary cause for the change in values.
If someone is really deeply invested in the end of his life (deeply un-invested in living his life), then he will succeed any way. When someone is committed to no longer be part of society, then how can he object to a little restraint?