We are just about coming through the other side of it - so I know what you are both going through now.
One thing that really helped us when there was complete nap refusal was a little quiet time after lunch. Here, the only way I can acheive that is to give him his drink of milk, snuggle under a blanket and stick the telly on. Not ideal, but it worked for us. He'd have about an hour just chilling out, recharging the batteries, and it would really help. In the early days, he'd even fall asleep
, but it was important that I made clear to him I wasn't expecting him to go to sleep - we call it his 'little rest'.
We often still do it, and it really helps him get to his (now much earlier) bedtime, and it gives Mummy a little break too