Mobile home ceilings provide a serious repair challenge because of the way they are constructed at the factory.
At the factory they have an enormous platform on which they lay out the ceiling and glue it all together. A crane then picks it up and sets it on top of the walls where it is fastened in place. That means the ceiling panels extend over the top of the walls and that individual panels are glued to the trusses.
If you have to replace a ceiling panel you have to cut the old one out and then bend the replacement to slide it into place, nail/glue it in place, tape the seams, and match the texture. This is not an easy process. It is complicated by the fact the old panels will have various amounts of dust and dirt on them and so a color match with the new panel is difficult.
As far as I know, replacements for the 4′ x 14′ ceiling panels are impossible to find. They were always a problem because you had to buy a bundle of 100 and they were so fragile that 50% breakage was possible. That, combined with the difficulty of installation and use of different materials in newer homes lead to their being discontinued.