Have been successfully controlling an arduino uno board with python serial libraries on my own computer  but would like to use google colaboratory so my grandson can plug and play without having libraries installed on his computer. can serial libraries be imported into the colaboratory notebook env?
You can easily install any package in Jupyter notebooks by inserting a bang command such as !pip install pyserial.
Unfortunately, this isn't really what you're looking for. Google colabs running remotely from your computer (this is in large part why they're popular as they can use googles beefier hardware). This means you would be installing pyssrial into a server computer that has no local access to your adruino.
I would recommend exporting your code as a notebook and getting him set up locally on his computer with the Jupyter environment. Obviously this is not as plug and play as you want. I can't really think of an easy way to get as plug in play as you want with configurable scripts.
Are python serial communications libraries available in the google colaboratory online dev environment?