It's a horrible horrible feeling as I know only too well. It happened to DH several times in the 1980s. It feels like the the rug's been pulled from under your feet. However, each time he went on to get another job but the best outcome was when he set up his own business with a friend. If only I'd known then what I know now I'd not have crippled myself with worry.
I'd not really considered how the extended family might have felt as we were so wrapped up in our own fears and concerns. Dear MiL just turned up with a cheque to cover the mortgage for a few months. My parents organised for us to have a little holiday which was a bit of a break.
Do talk about it with them. We somehow didn't discuss it with the parents. DH felt ashamed (which was ridiculous) not that it was his fault. I think it might help your DD to be able to talk about it. Can you look after the DGCs so she can get going on necessary CV stuff, job applications and, hopefully, interviews.
Chances are things will be OK but the not knowing is so scary.