Name: one-eye-luke US.Vet. Texas (Zone 8a) Quitter's never Win
Your snake plant is planted too deep in the soil and would benefit from removing a little of the soil off the top. The damage is from drought or not enough water at some point in the past. You can cut off the dead part. I hope your plant will recover..
NOT A EXPERT! Just a grow worm! I never met a plant I didn’t love.✌