Good luck to your husband. I know the materials used for the TC roof can be pretty disappointing when you get to rip them apart. The roof on my Shadow Cruiser hardside turned out to be similarly pathetic. I replaced the board with thicker marine ply. However, your husband will need to take care not to go too heavy since being a pop-up you still need to be able to 'pop it up' and not have it damage the pop-up mechanism.
I suspect the Palomino roof is fairly simple and you have the advantage of being able to remove the whole thing and do a proper job repairing it on the floor rather than balancing on ladders or scaffolding.
Here is the rebuild I did on my TCI did opt for a heavy duty welded aluminum roof, but you certainly don't have to go that fancy. It would be a good opportunity for your husband to consider any roof mounted accessories or wiring he might like to add.
Good luck, and do post pictures of the project as it progresses.
Steve.