One of the best ways for students to understand a sustainable business would be to operate one.
This does not have to be an end-to-end business. Although, this would be really interesting - especially if the students could invest/re-invest the profits and sell on a small scale e.g. pop up. But, on a smaller scale, they could partner up with producers/suppliers of sustainably developed clothing and business students to sell and market the clothes/accessories etc. locally. They could learn more about the sustainable fashion in a practical sense and understand the challenge of balancing sustainability (environmental and social) with covering costs and making a profit.
These pop ups called also travel e.g. to Berlin, London, Milan etc.
Here are some international orgs you could partner with - https://www.theguardian.com/sustainable-business/sustainable-fashion-bl…
More local ones - https://www.terumah.ca/where-to-buy-ethical-fashion-amsterdam/