This may be a controversial opinion but I believe your friend it right and it is your fault. Partially. Hear me out before you downvote.
I believe that if you're trying to tell a friend, or anyone you care about crypto - that you have a responsibility to that person to educate them about the potential pitfalls and risks. The fact that your friend went to watch bit-boy like youtubers tells me that you didn't warn him about that at all. If you did, he's an idiot, but I feel like you would have mentioned in your post if you did. The fact that you didn't, and may have not warned him about other pitfalls, set your friend up for failure.
Is it your responsibility to babysit his financial decisions? No. But you know damn well that most people who enter crypto know next to nothing about it other than what you told them. So where is the place every 20-something goes to learn about something? Youtube. And you know what that's like. 1 decent youtuber amongst 20 shitcoiners.
I'm not saying to let others know how much you invested, but you shouldn't keep knowledge about how to get into crypto to yourself either. If they're interested, teach them about blue-chip cryptos, bit-boy idiots, shitcoins, that it's an investment and can/will drop significantly, it's a long-term investment and over time should make money but there's no guarantee so do so at their own risk, etc.
If you just went to your friend, said you made money on crypto and promoted it but didn't prepare your friend for the dangers involved - that's at least partially on you (even if it's mostly on them). If it was a passing thought and he just went balls in, that's on him. You didn't clarify, and it seems unlikely that's what happened.
It's easy to say DYOR but lets be honest, it's a cop-out. There are too many bad sources of info out there that are either outdated, biased, have a different goal in mind, or just wrong. There's great stuff out there, but the average person new to Crypto won't find them through the slosh. Help them out. Or be a part of the reason why they fail.