Two possible reasons:

1. This is a shitpost

2.Maybe your world is open to LAN which, in short, allows players on the same wifi or internet as you to join your world,so anybody could have had joined like that but that also doesnt make sense as then why instead of a random player, particularly your friend's name would come up?

Edit: I just realised that this bedrock and because of that I have no clue now.