Alaus grubs aren't too difficult to rear or feed, they just require fresh invertebrate prey, you can bury smashed bits of mealworms or roaches for smaller instars, and can move on to live prey for larger ones.
Coconut fiber seems to work fine for a substrate, but when it comes time to pupate, they'll seek out large pieces of dead wood to bore into, (doesn't have to be rotten, just dead). In my experience with A.melanops, their larvae just won't pupate without this wood chunk, but apparently other Alaus will settle on top of their substrate and pupate there after a while.
Adults just eat fresh fruits, and would probably accept beetle jellies too. Obviously larvae need to be separated from a young age, as they are predatory and quite cannibalistic...