What advice should I give him?
You know his flaws and like you said, you have strengthened him up for good trading indications and strategic trading of taking profits accountabilities and as well setting up the stop lost bots.
You did not talk about his financial management which could had been one major problem for him but ideally, he should not just trade on any listed crypto coins as due to variabilities of liquidations, he might just get tied of stocking useless coins.
He should be contented with any small profit but in a continues pace he would make it huge.
That's nice if he is tired on those useless coins. They are useless anyways but there are also useless coins ( meme coins for instance ) that still can pump sometimes but of course, those coins with utility are still much better than them. Small but continuous profit sounds nice to you and me but not for others. For them it is better to earn huge even if it's rare to occur.
As long as they are not losing, I think there is no problem with that. Not all cryptos are legit or good in quality despite being listed, so yeah that we should not try and trade each of them. He already know his friends flaws, so this should include knowing how his friend manage his finances.