Strange. What I would try :

  • Send a sms with your mother’s phone to your phone number with : 2222 LOCATE STOP | Replace 2222 with your pin

  • Go on my.avast.com and check if the GPS icon just under your phone number is highlighted. Even if it’s not, I would try to enable Continuous tracking then disable it again. Your phone has to be connected to internet while you do this on the web portal.