How long is it supposed to it take for a minor meniscus tear to heal?

Depends. Most meniscal tears cannot heal themselves. See a fellowship trained sports medicine knee surgeon, to see if you require arthroscopic surgery.
Meniscus tears. Most meniscus tears do not heal. Minor or major, the problem with the meniscus is that it is an avascular fibrous remnant and doesn't have a blood supply to allow it to heal.