Also ask your tech person to install this plugin;
https://wordpress.org/plugins/better-wp-security/
It changes the default user name, login URL and looks for suspicious query strings in URLs etc.
Most people don't need all this but whoever hacked your mom's blog most likely left a backdoor they can use to get back in later.
Let me know by PM if you decide to go ahead and need any help.
Cheers,
Paz.