There comes a point when patches won't do the job. That point may arrive slowly or, in the case of the recent hurricanes, it may come overnight. Then it is decision time.
With a wood/shingle roof conventional roofers may be able to repair and reshingle. Metal is not so simple.
I think holes punched in metal roofs could be fixed by fastening 1/4" plywood under the remaining metal, secured by glue and screws to the trusses. The whole area could then be covered with Peel & Seal™ for a reasonably long lasting repair. However, I have not tried this myself so I can't comment on difficulty or cost.
I have also seen plans for "roof-overs". Treated wood posts are placed alongside the home and used to support a wood and metal roof that completely covers the existing roof. It can be done in a way that looks nice and is very effective.Since a roof-over doesn't effect the actual mobile home this is a project for which most any general contractor should be willing to bid.
I would caution everyone to think carefully before doing such a project.I know from painful personal experience it is EXTREMELY easy to drop more money into a mobile home repair than you can ever get back out of it. I did it several times before I learned my lesson.
I would never spend more than $4,000-5,000 without first checking prices for a replacement home; either new or used. There are situations, such as grandfathered lots, where replacement is not possible. It will come down to each individuals situation, but a replacement home may make more financial sense then pouring money into fixing the old one.