Not sure this suggestion would be timely enough - Beefconnections routinely sell beef soup bones with their deliveries, next up is in March. It is usually a buck a pound for their local herd. However they do have organic beef too and I am sure you can call them and arrange ahead of time to get the organic bones.
Fresh From the Farm (Donlands and O'Connor) carries them.
I'd call first though to make sure they're in stock; sometimes with FFTF you need to order items.
ETA: FFTF carries both organic meat and meat that is hormone and drug-free that is raised by Mennonite and Amish farmers (i.e. not fed organic feed)--not sure which category the soup bones fall under.
http://www.twincreeksfarm.ca/. Call or email to get in his list.
Gerald is in town every couple of weeks in the winter and every tuesday in the summer. He'll be in Toronto this Thursday, I think at College/Dovercourt. He has amazing soup bones, mostly shank bones. He naturally raises healthy and happy cows, lambs and pigs. If it's marrow bones you want, he's your guy. I hope your mum gets better soon.
Check with Cumbrae's or the Healthy Butcher, multiple locations in the GTA.
The Healthy Butcher
565 Queen St W, Toronto, ON M5V, CA
1636 Bayview Ave, Toronto, ON M4G, CA
481 Church St, Toronto, ON M4Y, CA
298 Eglinton Ave W, Toronto, ON M4R, CA