Demande d'aide sur un type bool

<?php
include_once('src/db/connect.php');
class ModelParticipant {

	private $connect;

	public function __construct(){
// Récupération de la connexion à la bdd
			$cnt = new connect;
			$this->connect = $cnt->setConnection();
		}

	public function read(){
// Récupération des données événements
		$info = array();
		$nbr = array();
		$req2 = $this->connect->query('SELECT id, name_ev, date_ev FROM event ORDER BY date_ev DESC');
		$res = $this->connect->query('SELECT id, name_ev, date_ev FROM event ORDER BY date_ev DESC');
		while ($data2 = $req2->fetch()) {
			$id = $data2['id'];
// Réucpèrer le nombre de participants
            $req3 = $this->connect->prepare('SELECT COUNT(id) AS nbr FROM participant WHERE id_event=:value');
            $req3->bindParam(':value', $id, PDO::PARAM_INT);
            $req3->execute();

            array_push($nbr, $req3->fetch());

			$req3->closeCursor();
		}	
		$return = array("res" => $res, "info" => $info, "nbr" => $nbr);
		return $return;
	}

	public function readDetail($id) {
			$req = $this->connect->prepare('SELECT id, id_event, name, lastname, fonction, tel, mail, particip, dej, din, ateliers FROM participant WHERE id_event=:value');
			$req->bindParam(':value', $id, PDO::PARAM_INT);
			$req->execute();
			$req1 = $this->connect->prepare('SELECT ateliers FROM participant WHERE id_event=:value');
			$req1->bindParam(':value', $id, PDO::PARAM_INT);
			$req1->execute();
			$atelier = array();
			$i = 0;
			while ($data = $req1->fetch()){
					$at = explode(',', $data['ateliers']);
					$atelier[$i] = "";
					foreach ($at as $key) {
							$req2 = $this->connect->prepare('SELECT name_atelier FROM atelier where id=:value');
							$req2->bindParam(':value', $key, PDO::PARAM_INT);
							$req2->execute();
							$nameAt = $req2->fetch();
							$atelier[$i] .= $nameAt['name_atelier']."<br />";
					}
			$i++;
			}
			$res = $req;
			return array("1" => $res, "2" => $atelier);
	}