Johnny Walker would be fine.
Johnny Walker, Dewars sucks. If he likes scotch get a single malt. Glenlevet, Glenfeddich are what I get because it’s easy to find. That price range or above.
Go to a store with a good selection. They will know what sells well in premium brands.
You can spend as much as you want. If he’s work $100 buy some $100 scotch, if he’s worth $50 buy some $50 scotch, if he’s worth less than that why bother.