Hello and welcome to BW forums
The night waking might be caused by his day time nap routine. Would you like to post your routine to include:
WU (morning wake up)
E (eat, milk/solids put these throughout the routine)
A (activity - how long he is awake)
S (nap time, the time he falls to sleep, the time he wakes up)
A (how long) (if there are 2 naps please show both and all the A time before and after)
BT (bed time, what time he goes to sleep at night)
NW (times, length, mood)
We might be able to offer some suggestions for you.
It would also help to know any background for instance is he an independent sleeper for nap and BT or do you need to help him fall to sleep?
What sort of sleep training method did you use?
It would also help to know if your routine is relatively consistent or if it changes daily. If you are using A times (how long LO is awake) to judge when to put down for nap or if you use set nap times and set BT (same time every day).
Hopefully we can help you find a suitable routine and get him sleeping through the night again