My Mom is 90, blind and mostly deaf. When she enters hospital I stay 24/7. Did so 2x in past 12 months. What will hapen now with Covid-19?

I doubt any hospital will do an admission on her right now
All have, are or will be approaching full occupancy due to Covid-19 by next week unless you live in a very, very rural, low population area and have a large community hospital with a critical care unit with deep existing inventory of PPE. Hospitals are discharging all patients that they can right now to create beds for Covid patients.

Your mom with her health history and I’m assuming is over 80, well, she is the demographic for whom Covid is fast & fatal. If she goes into a hospital, she will be exposed to Covid. It’s a harsh reality.
I’m with the others that now is the time to ask her doctor to write a script for her to get onto in-home hospice, which is a MediCARE benefit.

Depending on the hospital, some are letting one family member in, but that family member must stay (can't come and go). If you look up the hospital online that she went to in the last year, they will likely have a statement on the Home page about their Covid-visitor policy.
Like WorriedinCali, I would think that with her advancing health problems, the hospital is the last place she should be. Perhaps it is time to call in Hospice? They, in my opinion, are a Godsend.

Theres not much you can do. It’s highly unlikely the hospital will let you stay with her. Maybe you could consider bringing in hospice & focus on quality of life now & forego any more hospital stays?