There has got to be gun shops in Calgary that sell 1911 recoil springs but I don't know which ones they are.
If it's just a spring and guide rod then it is very simple. If the gun has something like a recoil master in it then it can be bit more complicated.
If it's just a spring and guide rod find a shop that sells them and try a few. They are fairly cheap. Stock should be around 16 lb and if he put in a heaver one who knows what it is. You can get them all the way from 6 to 20ish pound. Maybe try a 14 and a 12???
If you can't find locally you could order from Freedom ventures.
https://www.freedomventures.ca/produ...-recoil-spring
Good luck