So sorry to hear of your loss - both home and damage to your treasured quilts.
Beyond contacting a textile museum as was suggested, I could only suggest putting a large sheet in your bathtub, then laying the quilt on top of that. Use a mild detergent (like liquid Dawn dish soap) if not a textile-specific product and lots of water. Gently swish the soapy water over/around the quilt. Rinse/repeat until clean. May take several repeats. Lift the wet quilt out via the sheet and lay flat to dry. If they are bed-sized quilts you will probably need help to do that part.
You could also roll the wet quilt/sheet combo in some towels to help 'wring' the excess water. That is how I used to get excess water out of cleaned/wet needlepoint canvas and and cross stitch work so as to not distort the piece.
Good luck with your cleaning and rebuilding.