Honestly, if he's getting too cramped sa duyan, maybe it's time na mag-upgrade to a toddler bed or kahit regular single bed na may safety rails para sa sides, mas spacious siya at hindi siya maiinitan tulad ng duyan kasi may airflow. Try mo rin i-put ang fan slightly away from the bed instead of directly on him, at maybe cotton bedding lang para mas breathable, then once he's comfortable sa new bed during day naps, mas madali na rin syang i-transition to sleeping without you eventually.