Being burnt to that extent is terrible, I'm glad he survived although it must have been difficult for him and his family.
My sister has a friend who was a paraglider and a few years back he lost control and collided with an electricity pylon. He survived but sustained 3rd degree burns to almost 70% of his body. He is still healing years later - it's a long road to recovery.
I'm sorry you had to see your teacher that way, hopefully there will be good memories with him in the future that will replace those.
Thanks againThank you @andrastia ... Yes it was a terrible experience. My teacher is still healing too. He even considers plastic surgery on some parts of his body. I don't have his permit I would have shared his photos.