I really admire you for taking the hospice respite. All caregivers deserve it. Our hospice has offered to transport my mom to the hospital for up to 5 days, but I just haven't had the nerve to do it. My mom would absolutely freak out, her heart rate would go through the roof, and she'd probably die before they could transport her.
Your mom may not have totally comprehended what was happening until the social worker showed up. Just try to remember that they are professionals and will keep a close eye on her. They would also let you know if she was in any immediate danger of passing away while you are gone.
Please go and try to enjoy this event with your husband. You deserve and need the break. Sounds like fun too.