Still our brain is, for all practical purposes, a classical machine. No quantum effects are observed at the neuron level. So we can't use indeterminism to save free will.
Luck are unexpected good things that happen to you and that you didn't work for. It has little to do with randomness in a physical sense and thus philosophical discussions about determinism aren't really relevant in this context.
Look further down the discussion chain. confluence has been telling people to "learn physics" and seems to be equating luck with random chance or determinism.