Minecraft PE my friend and i cant join each other's world

I can join anybodys minecraft game except for one friend. We cant join each others game and all my other friends can join me and him. He hosts most of our worlds so i have no purpose for this game until i can connect to him.

for me at least when I've added friends on PE, no one gets a notification, its just if both people add each other, then you become mutual friends and can join each others world, realms, etc.

I need you to change my minecraft pe so then i can join to other ppl or friends

Same here. The friends tab in Minecraft xbox changes the number underneath it as my LAN friends enter their world on their devices, so xbox is definitely recognising that they are there. I see that number change within seconds of them starting on their
device. But underneath that, it still says "your friends are not playing Minecraft right now" when they quite clearly are. My friends on other devices see each others joinable worlds, but I cant see those same worlds from my xbox. They can see my xbox worlds
and join, but i cannot see theirs. Help!

Is it possible that one of you or your friends has joined the Minecraft Beta Insider program?

If so, you probably have different versions of the game, and only players with the same Minecraft version can join each other's worlds.

Check that you all have either the official Minecraft version of 1.11.4. If one (or more) have the current Beta version of 1.13.something, then you can't join each other's worlds.