if it is already uprooted and dead, sure you can dry it and smoke it. Wont taste amazing or be the best stuff ever, but it will still work if there are crystals developed.

However, My plants looked worse then that after 4 days of emergency neglect (its hot in there, they need watering almost everyday and I hadnt watered in 2 days already). I trimmed off the dead leaves, watered em up, gave em a day, and they were mostly back to normal. It looks rootbound or something.