If you take the term euthanasia in its original meaning: a "good death," "nice death," or "good dying" from the point of view of the dying person and their loved ones, then that's okay for me.

Should someone want the treatment (even if only in old age) I would never refuse it. For me it would be like refusing a cancer therapy to a prisoner. For me, that would be unethical.

And yeah, no gov or a person or a ngo should force someone to take the treatment.

If we fight the disease via cell regeneration, it could be that our cells will eventually start to get sick again and treatment will be needed on an ongoing basis. This would mean that one can decide again and again.