Hi Candi and welcome to GoY, there is no treatment for blight once it has affected the tomato plant organic or inorganic and I have never heard of using powdered milk to treat any plant disease. There are chemical sprays you can use prior to the blight starting but would you then want to eat the fruit?

If the actual tomato fruits aren't infected them you can pick them and take into the house to ripen, keeping a watchful eye on them. The plants, and the soil if the tomatoes are being grown in containers, needs to be put in your wheelie bin. If you are growing the tomatoes in the open ground do not grow any vegetable from the solanum family there for several years, the longer you can avoid doing so the better, as the spores will remain in the soil.

Candi, I had late blight on my tomatoes and someone suggested growing them under plastic, ie no rain falling on them. My husband made an A-frame from rebar (metal) and put plastic over. I can stand up in this and it houses roughly ten plants in two rows. I have not had any blight since but I always water by hand, never overhead. I cut off the leaves which touch the ground. I keep a round plastic dustbin in there full of water also a watering can. When bin gets low, fill it up. This way the water is about the same temperature as the tomatoes. There is a photo of this frame in one of my photos of the veg. garden.
Clementine