Free will only makes sense in terms of relative degrees of mental flexibility. Mental disorder, itself a matter of degree, constrains this flexibility. No brain is entirely “free.”
Euthanasia has been legal in Canada since June 2016. It has broad support. Applicants are carefully assessed and the process regulated. Slippery slope fears have not materialized.
Do you ever wonder where purpose comes from? How is purpose even a thing? How did it arise in a spontaneous, unguided universe, from nothing at all?