Proof that the Perfect cannot change and therefore has no will, short version:
The Perfect cannot get worse, by definition.
The Perfect cannot get better, because that would imply a better existed, which would mean the Perfect isn't perfect. Proof by contradiction.
All change is either getting better or getting worse, or we contradict the proposition that non-identical things are non-identical.
The Perfect cannot change.
The Perfect cannot make decisions. (A fortiori: decisions are themselves a change from a pre-deciding state.)
The Perfect has no will.
The Perfect is not alive.