Maybe "right" would have been a better US translation, at least in some states. Apparently if I was writing US''n dialogue i would get that wrong too.
English speaking Canadians do tend to be more active in listening; nodding, murmuring or saying confirmations (this is not considered interrupting) and the speaker's eh invites that. It is also used to turn a statement into a question rather than changing the word order or merely added onto the end of a question or sentence for emphasis. Or it may merely be a verbal tic, more common in the east as I said.
"I don't know, eh?" would usually mean "Really, I don't know." This is a good example of foreign written dialogue.
What part of the true north is your Mom from?