If my husband and I eat on the rooftop, what kind of dress code should we expect? Can he wear jeans?

Yes. Jeans an a polo or a shirts is perfecly fine. Enjoy 😋

Nice jeans are fine paired with a button down and nice kicks. Don't be that guy in the shorts i saw

I agree with Roland, it's pretty casual. But it really depends on the hour. Lunch, of course, is more casual. I'd dress it up a little for dinner.

Yes last time I had a button down short sleeve shirt dress shorts and dock siders shoes

A nice pair of dark jeans would suffice.

That might be too casual. I would say smart casual might be better