And we've also got eyes, which in principal means that many life forms already have quantum-sensitive apparati, right? Magnetoreceptors as well, and they're also found in "lower lifeforms" in various different forms from the basest phototaxis to extraordinarily refined lens systems which can numerous wavelengths.
And then I suppose when talking in scale — what does it actually mean — to flip that coin when you've only got an N of one in reality.
Of course I would have to concede that I accept an element, even a large one of determinacy, but my experience also precludes the idea of it existing exclusively. I'm really just pattering away right now, frankly I know very little of quantum physics (nothing, really) it's just nice to know someone is willing to furnish a hypothesis contrary to what I believe is the consensus on the topic.
But a quantum physicist would then ask "to what degree?" because quantum mechanics is very deterministic over large sample sizes (and a few trillion proteins in the brain would be a very large sample).
More importantly though, free will implies the ability to make a choice and that has problems when you invoke quantum indeterminacy to explain it: you don't get "a choice" you get random chance deciding things (and other depressing ideas like "human consciousness can't be backed up, saved or transferred - we really are trapped in these meat prisons and doomed to suffer).