#torn canvas

WHEN CUPID CRIES 2018 - 1524mm x 1219,2mm, Oil on canvas, found objects of wood, animal skin and granite

I have not personally repaired a torn canvas before. That's usually a job a framer will pass on to a conservator. Many framers have a trusted conservator that they use regularly.

If you are set on DIY, depending on how crafty you are and how bad the gash is, this may be a job you could tackle yourself. It's a pretty involved job though which involves sewing the tear and repainting the damaged areas on the front of the canvas. All in all it seems to require the expertise of a professional. The images below are from the Gainsborough Products website which sells a kit for canvas repair. 

Since a painting from your mother, if nothing else, holds sentimental value, I'd highly recommend investing in a professional fix and finding a local conservator. A good one can practically work miracles. Just make sure to find someone based on recommendations and ask to see images of their work. You wouldn't want your painting to turn into this botched restoration effort...

Hope this helps!