Most aren't looking to bad, but your heirloom semp has sustained quite a bit of damage.
If the plants are dry you can use a small paint brush to gently brush out the debris. If that doesn't work use a gentle spray of water to wash the debris out.
With your grandmothers semp I would gently remove all damaged leaves, if necessary replant them. I see signs of healthy growth. I believe they will make it.
I would love to see more photos of their progress as they start to recover.
