
Agree with everything thing that JG has outlined.
I have 2 half siblings, same Mother but different Father and I wouldn't dream of pairing them

for all kinds of reasons.
Why don't you talk to someone who's very experienced in the particular breed that you are referring to. They really are the best people for information like this.
And even then, presuming that your friend is a novice, if I was her, I would expect to have owned the breed for several years before I even thought of breeding full stop. It's a huge responsibility and expense, even for breeders that are well seasoned and have had their breeds for many decades.
Does the world really need more puppies in it when there are very experienced, good breeders out there that produce healthy, quality pups? This is a question that you should really ponder on. ;)