I agree with people who say that he didn’t need to steal anything and could’ve just put some work to develop and re-develop various algos.
Though perhaps he was the author of some great algos and felt they belong to him - but that’s still theft. IMHO he should simply return all the computers and IP that he stole, which would set him free.
As for shelf-life of algos, there are definitely some algos that can last for decades, as well as some old algos can be repurposed and reoptimkzed. Sometimes it’s not even the algo but the approach/methodology of coming up with algos. So he is still set for life if/when he simply gets back to working on those.