My mother who is 80 years old just found out she has the coronavirus? What are the chances she will survive?

It depends on her overall health and presence/absence of pre-existing cardiovascular and respiratory problems.  The average mortality rate for an 80-year old is only 8%. If she is in good health, her odds of recovery are 92% or more.  If she has health problems, her odds of recovery are much lower than 92%, and are dependent on the severity an nature of pre-existing illness.

not everybody who gets it dies and her chances are good she will live

There have been people over a 100 years old whom survived it, and healthy younger people in their 20's with no chronic illness who have died from it. There is no way to be sure just how likely she would survive it.

https://www.youtube.com/watch?v=B7YWZuzT1ug

https://www.youtube.com/watch?v=AJRMEmvMB24