A double wide is just two 12' wide sections placed together. The span of the 2" x 2" trusses will be only 12'.
The easiest solution would be to determine how many trusses are broke and purchase some from a mobile manufacturing plant. Any company that sells mobile homes would have the connections to get you some. The plant would probably just ship them out inside the next unit the distributor buys. I've had the misfortune of having gone through a roof and had to purchase a new 4' x 12' textured ceiling panel.
By going through the manufacturer you are assured of an engineered truss as they probably use stress tested wood to build them with. I would probably advise your family member to go this route or get their insurance company involved if only to keep the roofing company on the straight and narrow in getting this repaired.
Mobile homes are built with 2x2's but they are not made out of normal wood. These little 2x2's are extremely strong and extremely difficult to break. Only complete and total idiots could achieve this type of damage. I've roofed many double wide mobile homes over the years and never had a single problem of that nature. I always told anyone helping me to make sure they lay down the new bundles gently, even on a house roof but especially a mobile home. Throwing the tear off from one side to the other is just double work and makes no sense. I'm sorry that your family member didn't find a better company to do the roof for them and hope they get everything fixed properly on the next go around. :(
If I remember right, we just threw a 2x4 in when we had to......been a while tho.