Was? Dead? What did he mean?

I was talking to this guy about food, and I asked if his mom taught him how to cook when he was still living with her (he moved to my city 6 years ago). His response was: "...my mom was a great cook..." When he used the word "was", did he mean that his mom had already passed away? If not, why didn't he use "is a good cook" instead? I barely know him so I did not want to ask any personal questions. 2 cents from anyone is appreciated. :)

Thank you

There is a possibility that the speaker might have referred to a period in the past (when he was living with his mother), and that is why he chose was instead of is.

The one thing clear is that she is not a good cook now, or that now he no longer enjoys her qualities as a cook.

The speaker did not opt to say

My mom used to be a good cook.

But even if he did, the mystery remains.

So unless you hear more about her from your interlocutor, I do not think you can be sure.