All three soundbars you mentioned are good, but they’re a bit different. The Sonos Beam Gen 2 is really clean and easy to use, but it costs more. The Sony HT-S2000 is honestly the best value; it still has Dolby Atmos, sounds great, and is usually cheaper. The Samsung model sounds nice too, but it’s on the pricey side.
The only thing is that none of these are really meant for camping since they need to be plugged in. If he wants something for the trip itself, a portable Bluetooth speaker like the JBL Charge 5 or UE Boom might make more sense. But if you’re just getting him a soundbar for home before he goes, I’d pick the Sony HT-S2000 for the best balance of price and sound.