2 year sleep regression?

My son is going through what I think is an awful 2 year sleep regression. He goes to sleep no problem but I can’t for love not money get him to stay asleep! He wakes up probably 3/4 times a night and only sleeps max 3 hours in one block before he wakes again.

He used to sleep brilliantly but hasn’t for a few months now! He’s also going through a pretty bad case of stranger danger and hides from anyone who he doesn’t know. We’ve been working a lot on this and seems to be getting better!

Anyone have any advice on how I can encourage him to sleep more while he goes through this phase?