How to create behavior like the $HOME variable

You need to set a shell option for this

shopt -s direxpand

either directly on the command line or in your startup files.

From man bash

direxpand
   If set, bash replaces directory names with  the  results
   of  word  expansion when performing filename completion.
   This  changes  the  contents  of  the  readline  editing
   buffer.   If not set, bash attempts to preserve what the
   user typed.