Shell deterioration

[Casey Freswick]

Have a couple of issues this summer. I think this is a long term situation that I have just realized as it has gotten progressively worse. The bottom corner of the front shell, when popped up it is just to the right of the sink, is soft. I am thinking from water seepage over a long period of time. When I knock on the wall of the shell there is makes a noise like when you would tap on cardboard. The outside is solid. One foot in is solid. The wallpaper this year was a mess in this area. I pulled it off. THe wallpaper just above sink was looked like it had been wet. Under that wall paper there is is a wood paneling. Thought it would be aluminum. I know water has gotten in here. I just bought 1/2 pipe insulators to put in the vinyl seals. So how do I fix the mushy wall? Will it dry out? It is a small area but not sure how to fix it.