It's hard to get my son 3 months to sleep in the day. He is an ultra light sleeper. After patting for 15 min, he only sleeps for another 15 mins before he is awake again. Anyone has similar experience?

Yes my no1 was previously like this too. He will only nap for short while but when he is out with me (stationary in stroller because I'm having lunch with friends etc) he will sleep for very long. Then I realised he was too hot at home and i started to turn on the aircon for his noon naps. since then he slept much better. Maybe you can see if you can change his sleeping place or maybe play some music. Maybe stimulate something like his night time sleep