My son will be 3 months next week

He just recently started sleeping through the night but he will not stick to his feeding schedule through out the night he’ll go down between 1030/11 his feedings are every 2-3hr sometimes 90 minutes apart. He won’t wake to feed & will be fussy until put back down. He’ll wake around 4 rarely 5 am to feed an we’ll do diaper change & feeding then he’ll go back down & won’t wake until 10am. He feeds on his schedule pretty good throughout the day but how do I get him to eat at night? I don’t want to under feed him...