Charcoal absorbs odors. He could try putting the tops inside a plastic bag with "Odoreaters" shoe insoles with the carbon in them. It would be better to use charcoal, but hard to keep the charcoal away from the fabric. I use the Odoreaters insole inside my featherweight case; got rid of the musty smell completely.
He could also try one of the Odor Begone products (available from Amazon). Haven't seen from the reviews if it works on smoke odors, though.
The tops can be hand washed if they are first basted to a foundation fabric to stabilize them. Again, though, I don't know if normal detergent will take out the smoke smell.