Xbox one and Xbox 360 friends

I think I sorted out the issue. support.xbox.com/.../view-xbox-one-friends-on-xbox-360

Xbox One friends don't automatically become Xbox 360 friends. The friendship only goes one way. Your Xbox 360 friends are your Xbox One friends but your Xbox One friends are not necessarily your Xbox 360 friends--you have to specifically add them on the
Xbox 360. That is good to know. Now I just need to figure out a way to thin the heard on Xbox 360, so to speak.

this may help

https://beta.support.xbox.com/help/friends-social-activity/friends-groups/view-xbox-one-friends-on-xbox-360

On Xbox One, a friend is anyone you’ve added to your friends list. Adding new friends on Xbox One doesn’t require that they send a friend request first.
When you sign in to an Xbox One console, your Xbox 360 friends will automatically appear in your friends list, as well as in your followers list. If you accept a new friend
request sent from an Xbox 360 console, you’ll see them as both a friend and a follower on Xbox One.

However, friends who’ve been added on Xbox One won’t automatically show up on your Xbox 360 list. If you plan to play with them on your Xbox 360, you’ll have to send a friend request through your Xbox 360 console. Once they accept,
you’ll see them in your friends list on both of your consoles.

If you go into the 360 game menu on the xbox one you may be able to see this.

https://www.youtube.com/watch?v=q7YhbokEf2U&feature=emb_logo

Have you tried having him send you a friend request? This is some information I was able to find. It might be worth a shot to have him send you a friend request.

Viewing your Xbox One friends on your Xbox 360 friends list

With Xbox One, a friend is anyone whom you add to your friends list. Adding new friends on Xbox One does not require that they send a friend request first.

When you sign in to an Xbox One console, your Xbox 360 friends will automatically appear in your friends list, as well as your followers list. If you accept a new friend request sent from an Xbox 360 console, you will see them as a friend AND a follower
on Xbox One. However, friends who have been added on Xbox One will not automatically show up on your Xbox 360 list. If you plan to play with them on your Xbox 360, you’ll have to send a friend request through your Xbox 360 console. Once they accept, you’ll
then see them in your friends list on both of your consoles.

Hi, yeah it will be because of the Xbox 360 friend list is full. There is nothing you can do, except remove any friends on your Xbox 360, and then invite your Xbox One friends via the Xbox 360 guide.

Adding a friend should work regardless of console. You can try to do it on the Xbox website if necessary.

Be aware however, that the Xbox 360 has a friend list limit of 100, so if you already have that many people on your friend list, you can't add that person as a friend.

Also, sending a friend request to the Xbox One doesn't show up as a "friend request". Instead, you automatically become a "follower" of that Xbox One user. Only when the Xbox One user friends you back, you are actually friends.

Also be aware, that you can't communicate from Xbox 360 to Xbox One, UNLESS the Xbox One user is playing a Xbox 360 backwards compatible game.

However, you can still use the Xbox app on a Windows 10 PC to participate in a party-chat with Xbox One users, without them being in a Xbox 360 game.