Hi Lindy, I have no connection to the families. I haven't confirmed that Hugh's family went west either. There is a Thomas and Ellen Cahill in the PEI 1881 Census but Ellen's age is forty-two so they may not be Hugh's parents.
I made an error in my first posting, Hugh's mother was Ellen Ryan rather than Grady. You will find Hugh and Ellen's Death record in the following site. https://familysearch.org/
When you open it, you will see little boxes to put the names in for searching but if you scroll down the page, click on the US and then you will see many sites, such as Minn. Death Records.