Aluminum siding bulging out. Unsure how to fix

Water damage is causing it to bulge.
I am willing to bet once it is pulled apart, all the wood has rotted.

Can't repair just from the inside.
The front cap needs to come off, at least.

That seal is horrible and that has let water in.

Over on glamisdunes.com, in the RV section, there have been a couple of people that have documented pulling their Warriors apart and fixing issues like this.

Might be worth the time to do some searching.