Tell your friend to figure it out himself. It's his 1000 pounds to lose if he wants to take the risk, not yours. It's not that difficult, he can find lots of information online about how to do it. You can even walk him though it step by step and show him which wallet to use, which exchange, etc.

Essentially this is the same as a friend sending you money to buy stocks, another currency, commodity, etc. It's being done on his behalf, so it's perfectly legal. He just should do it himself so he can accept full responsibility for his money.