...and to be honest I'm happy because my neighbors invest in bitcoin just like me...
Actually, the seller in the store acted recklessly, trusting your advice, obviously not understanding the fact that you yourself are new to investing. You should understand that if the price of bitcoin decreases after your recommendation to invest in bitcoin, then you will have to shop in another store, as the seller will consider you to blame for his losses.
Yes, I agree with you. Indeed, logically it is too rash to make an investment decision that comes from a beginner as well and the impact when there is a decline in Bitcoin the OP will be considered a fraud because the bitcoins are owned by his friend, and maybe with his friend there will be a misunderstanding at the moment later.
It's a good thing to invite people to invest in bitcoin but considerations must be taken into account if the OP doesn't want to be blamed if something bad happens to his friend.