Ugh, it is just NOT a fun situation no matter how you look at it
Most REs will have you freeze at least one sample ahead of time, because if something does go wrong on the day of the retrieval, you absolutely have to have a Plan B. Since Brian doesn't have any sperm issues, I bet it would be absolutely fine to use a frozen sample. People who use sperm donors do it all the time, right?
The only other thing I would ask about is if you guys can do the sample together right before the retrieval. Maybe it would still be fresh enough if you did it that way?
Good luck, Melissa. I'm so excited for your IVF journey to begin!