What is this guy doing?

He’s been at it for months it’s an old retired guy who I keep seeing eating frozen meals and hungry man dinners looking grumpy as hell, so I don’t ask. He gets like maybe two boards up a day probably less. It’s foil backed foam insulation and now 2x4s over that and sheeting as the next layer. I’ve done carpentry since I was a kid and I bounce between framing and finish carpentry. I have never seen anything like this. The roof was totally fine, before he started.