zombified at the peak of heroes

Hi, my grandma is playing 3 stars and needs help. She is at the peak of heroes and she keeps getting zombified. I played this game, but it was a long time ago and can't remember how to fix this. Can any one help???
Welcome and Enjoy!
https://www.aldorlea.org/officialsite/phpBB3/
https://www.aldorlea.org/officialsite/phpBB3/viewtopic.php?f=40&t=1576