My large sago palm's leaves are brown from freezes. The pups are still partly green and the lower leaves on the palm are still a little green. I saw some the other day that the leaves had been trimmed all the way back to the trunk, and I was trying to find out what to do.
Brown Leaves Caused by Freeze on Large Sago Palms
Certified GKH Gardening Expert
I am sorry to hear about your plants. Cut off brown fronds but don't cut any green growth. This article may help you with getting them to recover: https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm