Welcome to the forum, and sorry for your baptism by fire.
I can’t help with the window itself, other than to make some suggestions. If could post photos of what is left, and take measurements that will help a lot.
Also suggest you locate some Lexan sheet material [1/4” maybe?] and have a piece ready to go to cover the missing glass etc.. Round the corners and sand the edges smooth so that they won’t cut the tape you may have to use. Plus plenty of duct tape to rig up a temporary weather-proof road-ready patch.
Lexan comes in lots of shades that will match the trailer’s color, so combined with gray tape, the repair might just look OK.
Obviously you would prefer an opening window [like the original?], but a good patch should at least let you keep your engagement.
PS — NYC should have plenty of plastics fabricators who can fill your needs very quickly.
PS2 — Bob’s blue text is a hot link to a good lead, in case you don’t know this.