Nap without mom
The swing was the key for us when DD went through this phase.
I know you said he wakes in it too- make sure you are using it on a very high setting. It seems crazy, but they sleep better on the fastest settings. Also, do you swaddle? This might help too. And white noise- I can't say enough great things about white noise. Just loud static, water/ocean noises. It's got to be pretty loud and consistent too.
You might be already doing all these things. If so, I'm out of ideas!
Could you take a walk close to home and bring the stroller inside while baby is sleeping?
Any chance he would lay quietly and eventually go to sleep on his own? Mine just started this, and it shocked me. I started laying her down in the mornings in a pack n play in the kitchen so I could more easily get my older ones breakfast and give my back a break from wearing her all day. What do you know, she'll usually fall asleep if I just replace a paci a couple of times. So far it's most reliable for the first nap of the day.
She also usually fully wakes within 5 minutes of me setting her down -- just enough time to go to the bathroom!
Have you read the no-cry sleep solution yet?