These are all fairly inexpensive, except for the Field Guide. Have a lot of fun putting it together. Look for your local Asian grocery, they'll have a lot of this stuff for pretty good prices. Lots and lots of recipes and techniques are available on YouTube.
- a couple extra steamer tiers. It'll let him be making the next batch to steam while the current batch is already in the steamer.
- some of the little bitty steamers, maybe.
- Liners for the steamer. This helps keep the food from sticking to the bamboo. Some recipes use lettuce leaves, some use small individual liners.
- dumpling makers. These are gadgets that are time-savers.
- There are steamer utensils that are handy, like a set of tongs that will lift a bowl after it's been steamed. Or he can use a dry dish towel.
The Field Guide to dim sum: https://www.amazon.com/dp/1607749564/?coliid=I1KGSKVGDRWTA3&colid=2BK5MCG89QOWI&psc=1&ref_=lv_ov_lig_dp_it
Happy birthday to your hubs, and have fun!