That, I think is the fallacy of act being sold -- I admit I thumbed my nose at it when they were selling a gallon jug for something like $11 at whole foods last spring. They had an impressive looking set up by the entrance with jugs to fill from the spigot....
I think without the aeration the prime microbes that you are looking for in ACT will rapidly die off. It will still be good plant supplement, not the original quality that, for the amount of effort necessary and the associated price, you would be paying for.
If your friend were to take the ACT and immediately used it in the garden -- and remember AACT is concentrated stuff and goes a long way -- I think that would be best. Remember that it will need to be diluted with rainwater or other non-chlorinated water so as not to kill ff the microbes.
I've made house plant sized AACT with worm castings in a gallon jug using a very small aquarium air pump and wand-type air stone as well as 1/4 soaker tubing. Considering the small volume, biological activity may not have been as stable, but if you needed to, that would be an option for keeping your gift aerated. But the biology changes over time -- in matter of hours -- as the microbes undergo their life cycles, so no, AACT has NO shelf life at all.