Hi Ann
Congratulations on your success!
To answer your questions;
Yes, the protocol could help your friend to gain healthy weight.
Our members in the U.S. substitute Quark with cottage cheese. You could make your own quark, instructions are in the files section here. You will also find sauerkraut recipes in the same folder.
Dr. Budwig didn't specify fat content but it is widely believed that we should be using low fat quark/cc. Here in the UK, Quark is easily found in supermarkets and is always 0% fat and contains around 12% protein. If you have to use cottage cheese, try to find one with as close to 12g of protein per 100g.
The ratio of flaxseed oil to quark/cc is approximately 1:2. I say approximately as Dr. Budwig’s recommendation for one portion of her “cream” was 3 tablespoons of oil, 2 tablespoons of milk and 100 - 125g of quark (around 6 tablespoons).
I hope this helps. I'll also post another link to Sandra’s daily plan, for your reference.
Good luck.
Julie