Airline Travel Cancelled Due To Government Shutdown

Location: California

Hey everyone I've got a quick question maybe some of you can help me with. I left specific names of companies out to insure I don't screw myself if I have options, but the scenario is what has occurred.

I've got an upcoming trip to Asia with my wife and bought tickets for her Sister and her Boyfriend to fly from Mexico to the USA, meet up at the airport and then fly out to Asia together. They're both Mexican citizens and need a USA travel visa for the layover even though they are only transiting through the USA to their final destination.

Tickets were bought in December 2025 and they started the visa process at that time. Fast forward to current times and the US Government offices in Mexico have been closed and are not taking any new visa appointments. We scrambled to try and figure out options and the only thing we could do is reroute their flights to not stop in the USA or Canada as they require the same type of visa.

We initially booked them via a 3rd party service (think Expedia). I contacted the them and explained our situation. I had initially purchased the option to change and/or cancel flights and their only options they offered were to change the flights with similar layovers in the US and Canada. Cancelling the flights comes with hefty fees even though I purchased the cancellation option. Changing the flights to a much later date isn't really an option since they don't have nearly as much vacation time and we won't be travelling with them anyways. I provided the bookimg company with alternate flight routes but unfortunately none were with partnered carriers so ultimately there was nothing they were authorized to help me with which I understand. They even sent the request up their chain of command and we got the same response.

I contacted the airline directly and since the tickets were bought via a 3rd party, they couldn't help either. Again I understand this policy.

So my SIL and her BF cannot fly due to the visa restrictions and I'm out a few grand at this point.

Do I have an argument here? I'd like to recoup my losses. SIL and her BF took all the proper steps in a timely manner but since no visas are being processed they're stuck.

TLDR. SIL and BF can't fly due to US government not issuing visas right now. How can I get my money back?