Is 15% Restocking Fee Lawful in Georgia?

I live in Idaho, I’m helping my 93 year old father purchase his first hearing aids, he lives in Atlanta, GA. With my blessing, he went and had a free audiogram. But despite my strong advice not to purchase the aids the audiologist would pressure him to buy, he did so. He got some low end Miracle Ear aids for $4500. I think he can probably do a lot better at Costco.

He tells me that there will be a 15% restocking fee if he returns the ME aids during the trial period (30 days in GA, I think). Is this normal, lawful and reasonable?