Usually, but from here, my lawyer siut is at the cleaners trying to get out the stains.
Since I am an inspector myself, of course my opinion will be evaluated as "on their side". Guess it goes with the territory.
But as much as I do not like it...they have a point. When you get an inspection, it is usually only good for a year, but that also depends on your state laws. The problems you found should have called for an engineer to look at the issue. So in this case that may have been at fault for not recommending further evaluation. Don't get me started on larger inspection Companies, They have Lawyers.
But when you have work done to the home, the next professional owns it. The roofer is the next professional. If there is an issue with structure or cracked rafters, they need to look at it. If they are going to add new weight to a roof and change what is there, they need to be sure it is able to handle the changes. They are not only responsible for the roof, but what it is attached to. This is why real professionals are so expensive....experience. Where was the building official?
These are points that need to looked at by your lawyer and another professional Home inspector or expert. If that is the route you choose, make sure you have documentation of everything as it progressed.
I hate lawsuits, however I also do not like shoddy work from professionals.