They don't really need baths unless they've slithered through some poo, or maybe got some pee on themselves. Or, if you have a bad shed you can let them soak. But for the most part, they don't need baths
I believe he just wants to give his a bath. It wouldn't hurt anything. It's not necessary no, but it's harmless as long as it's plain water, and not deep and it's monitored.