Frank - Gord has two children with Brita - Fred and Ingrid who are in their early 30's I think. He has Eric with Cathy Coonley - he's about 17 or 18 coming up around Christmas and his two with Elizabeth, Miles and Meredith. His mum passed away 2 years ago this past May and his dad about 20 some years ago. His sister Bev lives up north near Orillia. He has two grandchildren I think but I'm not positive. I think they are his daughters kids. Someone else may have more details.
I have a bit more info to add here... last Nov 1999 Gord told the 5 of us backstage his dad, Gordon Lightfoot Sr, was born and raised in Paris,Ont and later moved to Orillia where he met Jessica. I was kinda bowled over there was another Gord Lightfoot at one time!! So it was neat hearing there is a local connection to Gord, Paris is 10 min west of Brantford.
To answer your question about his parents attending his concerts... I was at the Massey Hall 98 concert when halfway he paused for 10 minutes and spoke of his mom and her influence her persistence that he use his voice. He said that his mom attended every concert at Massey Hall since day 1 except for "tonight" Gord mentioned she was gravely ill and that her favourite song was " The House You Live in".... then he proceeded to perform it of course word was out 2 weeks later Jessica Lightfoot passed away. Can't tell ya if Gord Sr., ever attended any of the concerts