Elgg-Lorea-Hydra/mod/friend_request/actions/friends/removefriend.php

<?php
	
// Get the GUID of the user to friend
$friend_guid = (int) get_input('friend');

// Get the user
$friend = get_user($friend_guid);
if (empty($friend)) {
	register_error(elgg_echo('error:missing_data'));
	forward(REFERER);
}

$user = elgg_get_logged_in_user_entity();

// remove friend from user
try {
	$user->removeFriend($friend->getGUID());
	
	// remove river items
	elgg_delete_river([
		'view' => 'river/relationship/friend/create',
		'subject_guid' => $user->getGUID(),
		'object_guid' => $friend->getGUID(),
	]);
} catch (Exception $e) {
	register_error(elgg_echo('friends:remove:failure', [$friend->name]));
	forward(REFERER);
}

// remove user from friend
try {
	// V1.1 - Old relationships might not have the 2 as friends...
	$friend->removeFriend($user->getGUID());

	// remove river items
	elgg_delete_river([
	'view' => 'river/relationship/friend/create',
	'subject_guid' => $friend->getGUID(),
	'object_guid' => $user->getGUID(),
	]);
} catch (Exception $e) {
	// do nothing
}

system_message(elgg_echo('friends:remove:successful', [$friend->name]));
forward(REFERER);