Well, if your friend has been well-informed of the risks, the losses, and the potential headaches that may ensue with investing in bitcoin, I don't think you shouldn't absolve yourself of the pressure, after all you're not Jesus who could control the economy of bitcoin just to look impressive to your friend.

And he strikes me as someone who's smart enough to know what he's doing, he's probably thought about investing in it too, but is just waiting for a push from his friend circle. So I assume he pretty much knows what he's getting into, and if he's a good friend, he's not gonna blame you for any losses he may incur in the future.