How to allow WordPress updates to only one specific administrator?

SOLUTION:

We take this code and paste it to functions.php :

function createit_hide_upd_for_other_adm_users() {
    $current_user = wp_get_current_user();
    if ( 777 != $current_user->ID ) { //change the user ID
        add_filter( 'pre_site_transient_update_core', 'disable_updates' );
        add_filter( 'pre_site_transient_update_plugins', 'disable_updates' );
        add_filter( 'pre_site_transient_update_themes', 'disable_updates' );
    } else {
    }
}
add_action( 'init', 'createit_hide_upd_for_other_adm_users' );

You just need to find the correct WordPress user ID and put it in place of 777, thats it!