How Do I Send A Friend Request

That is because of his privacy settings….you can not send him a request unless you have any mutual friends with him.

To add a friend:

Click the search bar at the top of
Type your friend's name into the search bar and click . If you don't see your friend, try clicking People or try these steps.
To send someone a friend request, click Add Friend next to their profile picture. Some people might not have Add Friend next to their profile picture, depending on their privacy settings.

If you're having trouble adding a friend, you can try these steps.

Find More Friends

To find more friends to add, you can:
Upload your contacts from your mobile phone or other accounts.
From your uploaded contacts, you can add friends who already have a Facebook account, or invite people who don't have an account to create one.
Use People You May Know.