<?php
$users = [
['name' => 'Tirion', 'friends' => [
['name' => 'Mira', 'gender' => 'female'],
['name' => 'Ramsey', 'gender' => 'male']
]],
['name' => 'Bronn', 'friends' => []],
['name' => 'Sam', 'friends' => [
['name' => 'Aria', 'gender' => 'female'],
['name' => 'Keit', 'gender' => 'female']
]],
['name' => 'Keit', 'friends' => []],
['name' => 'Rob', 'friends' => [
['name' => 'Taywin', 'gender' => 'male']
]],
];
$val = [];
$us = $users['friends'];
$merge = array_merge($val, array_values($us));
$minValue = min($merge);
var_dump($us);