How do I respond?

My fiancé is in another state doing a post doc. Covid prevented me from going.

His sister and my best friend both texted me letting me know my fiancé’s brother is hosting a Labor Day get together.

How do I respond to my FSIL? She basically said that he was hosting a last minute get together. I’m so socially awkward and never know what to say.

Would you go? I want to go but part of me feels bad that my fiancé isn’t able to go.