No Avocados cannot be frozen whole otherwise the Avocado will turn out to be mushy and be a mess and also the Avocado will change it's taste and texture.
So while you could freeze whole Avocados it's not recommended to do so because the Avocado will basically be ruined.
Even when you slice the avocado up it still does not freeze very well.
But if you puree the avocado or blend it up and then place the blended or pureed avocado into a freezer safe container or freezer bag then it will be okay.
I will puree avocados and then place them in freezer bags and freeze them for later use.
I sometimes make guacamole or even just eat the frozen pureed avocado once it's thawed out.