Hi!
If it helps my DD is a similar age to your DS....we started getting EW's & BT resistance a few mths ago & so I started to cap her nap. Initially I capped it at 1.5hrs & it's now down to an hour. At around 2.5 yo their sleep needs can change quite a bit as they can handle longer A time & head towards dropping the nap completely
!
So he's currently getting around 10-ish hrs of sleep a night right? What was his previous WU time before the EW's started?
It might well be that you need to cap his nap a bit in the hope that he does a longer night. A 2hr nap at 2.5 yo is quite long. I would cap at 1.5hrs & stick with it for a few days to see if this helps his EW's.
Does this help?