If he made 2 mistakes and did everything right, then I think like this:
1. he confided in a stranger. It could be a swindler.
2.Maybe Peter invested almost all of his funds in bitcoin? He had heard about bitcoin, but not about other things, so he invested almost all his money in bitcoin? And the rest only a little.
If there is any other way Peter could have made a profit in this case, I'm curious to know. Thanks!