my daughter slept through the night until she started teething.
She got her 1st set of teeth at 5 months, and hasn't slowed down since.
In between sets of teeth, she'll sleep through the night. But she'll get up for like a week maybe a week and a half straight.
And all she needs in a lil orajel, and she's off to sleep again.
I'm sure teething has something to do with it.
If no teeth soon, talk to his Dr. about his sudden schedule change. His diet could need adjusting.
Sarah