2013 Toyota avalon battery problems

we have replaced 4 batters on our 2013 Avalon with only 47271 miles. orig.
  #2 battery replaced on 11/18/2015  17210 miles  #3  4/14/17  26845 miles    
#3 10/22/2019 47271   serviced every 5000 miles   every time they say every
thing checks out. on 10/22/2019 my wife was getting off x way and every
thing shut down. no steering or brakes . she is now afraid to drive it she is 72
years old. I think that Toyota's alternator  does not have enough out put at
idle to keep the car running .