Selling a personal residence to a business partner

[Maurice Etienne]

Hello all, my business partner has a personal residence that I would like to purchase. He is a few months behind on the mortgage and I plan on renovating and using as my primary residence. are there any regulations or restrictions I should be aware of in terms of this potentially not being considered an arm's length transaction? If we agree on a price that is below market? what are the tax implications? any price we agree on would be enough to make his mortgage company whole and to give him some cashback as well.