Please recommend a good place to treat sudden sensorineural hearing loss.

There is the mother of the older sister I am usually close with. I often visit and keep in touch with her mother as well. Suddenly, she experienced sudden sensorineural hearing loss, losing her sense of direction and hearing. When she went to an ENT hospital, she was immediately referred to a university hospital for emergency treatment and was admitted urgently.

My sister is very worried, and I want to help somehow. Has anyone experienced sudden sensorineural hearing loss?

I trust university hospitals, but I want to hear about prognosis and personal experiences.

I'm also very worried.