My son is almost 3 and has been potty trained for a few months, we have a few accidents here and there during the day but his nappy is never dry in the morning so I wasn't going to start trying without a nappy at night quite yet. However the last few nights he has woken up several times in the night, about 11pm and 2am, to use the toilet on his own but his nappy is still wet when he wakes at 6.30am. When he does wake in the night he is very distressed and cries until he is back in bed! Is he ready and how can I best help him?