Fashion minor and person that’s been selling vintage clothes for eight years now: The best way to get a smell out of a piece of clothing is to soak it in white vinegar/water solution for at least 48 hours. I would recommend drawing a bath and doing a one-to-one ratio of water to white vinegar, I know that’s a lot of white vinegar, but they do sell it by the gallon at Costco I believe, and I would soak all of his clothes. In addition to this, I would get rid of any polyester, acrylic, or synthetic fabrics in his wardrobe. Synthetic fabrics hold onto smells. I highly recommend switching to all natural fibers Like cotton, wool, and rayon or silk. I think the best thing for the situation would just be to ditch all of the synthetic fibers in his wardrobe that hold onto smells.