I'm surprised he still really wants one. I mean I have fish but still idg how watching ants seems interesting, like I already see them all the time being ants, you almost might as well keep flies... Then again, that shrunken people sidearc from Solar Opposites does give the concept some renewed appeal to me.
Sometimes I go outside and flip things over and find a bunch of ant eggs and various kinds of ants, I harvest the eggs to feed to my fish by using a Tupperware part full with water to make a bunch of crawling ants easier to separate and deal with. If you already have the setup, it seems like it might be possible to go out and collect a bunch of ants and eggs and populate the farm and let them figure it out, let a new queen emerge. Then again if they all just died quickly that might be hard to clean out and would be pretty upsetting. Also might be upsetting in general for him to watch these bewildered wild ants scramble to adjust to life in a suitcase with only a random fraction of their colony's population, no clear queen...