Unless it's changed fairly recently, it should be 35.

Call back and get it changed - it's amazing the re-issue even worked with an MCT violation. If he's lucky, everything is on time, and the connection boards across from or next to the gate they land at, it's probably not an issue. Anything more, which is highly likely, and could be problematic.

Back out the connection time, and you'll see. Start by subtracting 15 minutes, as that's when a passenger is required to be at the gate ready for boarding, and when a GA can start offloading pax. So that leaves 8 minutes. Say the flight pulls up to the gate on time, but it takes 5 minutes to deplane. That leaves 3 for him to get where he needs to go. If the gate's close by, it's not bad. But if the flight is 3 minutes late, it's already likely too late. And If he arrives on-time, at say, B18 and departs from E/F gates, you can forget it - will be lucky to be at the gate before the plane pushes.

Now maybe the gets lucky and UA holds for him, but don't expect that.