Tips, convince him to buy a real classic suit because, at least in my world, retired people still need one. My husband was a pallbearer last weekend, and we do attend funerals and an occasional wedding. His parents are in decent health but very elderly, and the need for funeral clothes at the ready is real. And to be honest, I would prefer to bury him in a suit than any of his casual clothing. Your situation in this area may be different, of course.
Fortunately he has a classic darkish gray suit bought in 1996 that is still a current cut and still fits, but if it didn’t, I’d insist on updating. It’s lovely and doesn’t look dated or worn, especially since I’ve kept his small tie and shirt selection current.