Hi and Welcome to the forums
That is likely above the aisle between the head and the galley,
Possible they got into the trees so have a look at the roof and check for other damage such as the tv antenna.
Take a ladder with padding on the rails
The vent is an easily replaceable assembly which is held together by screws through the flange surfaces
I believe ( and may be wrong) the std size is 14 x 14"
This gives opportunity to upgrade to recent improvements which will have a quieter fan, perhaps with a remote control...so maybe $200~$300 to sort out and when you are done you'll have a newly sealed penetration.
Some years ago when I was resealing ( and then washed and waxed) my roof penetrations I did it through the vent hole standing on a small step stool I was able to reach and work on the roof easier than from a ladder on the van.
you can likewise take advantage of the fan hole to work on other stuff.
that repair/replacement is no big deal
Fantastic fan and maxxair are 2 brands I know of- mine is the oem PleasureWay fantastic fan
here's a typical replacement- shows the anatomy of the parts
On my van I've added a maxxair vent cover which allow vent open in light rain...looks like a trash can on the roof and raised my clearance up 6" ( but now our highest spot is an easily replaceable cover rather than my expensive AC unit)
Mike