Your call on using it for now, totally understandable, but have you ensured that the leak which caused the problem to begin with has been addressed? You may want to Eternabond , or maybe use the new white liquid rubber tape on all the seams in that area to avoid worsening of the problem.
Delamination is a very difficult repair - and usually only done for small areas. Large areas such as in the photo usually require replacement of whole panels. A shop that does RV body work would be able to tell you what it would entail and give an estimate of cost.