This all gets easier...I never expected to get into snakes at all, but that ship sailed over 3 decades ago, lol. I'm an animal-lover & kept an open mind, even though feeding rodents bothered me at first. (I've had many rodent pets before I got into snakes...) It's so nice that you can share this interest with your son, & it should encourage him to read & learn more too.

(pretty sneaky, lol)
The locking hemostats are also called "clamps" in the medical world...they're used to "hold things" firmly, like during a surgery. Very awkward though for feeding snakes, & fyi, the 12" tweezers are the most comfortable to hold & use, at least to me, but if you're wanting 18" (over-kill for a ball python, IMO) you don't want the tweezers; for that length, non-locking hemostats are easier to use. 18" tweezers are too long to easily squeeze & control- too much distance to transfer your hand pressure effectively.
If you're wondering where to get them, here's one place I've bought from in the past:
https://tongs.com/
Here's a link to their giant tweezers:
https://tongs.com/product/tweezers/ They have them with rubber coated tips (good idea!)
https://tongs.com/product/rubber-coated-tweezers/
and they also have the hemostats in various sizes:
https://tongs.com/product/hemostat-straight/