Learn from my mistake!!!
I was in almost the exact same situation as you only the friend's dog was a different breed, but also a large breed. Out of control dog, crated all the time, never walked. They always kept it locked up when guests were over because their dog would be jumping, scratching, knocking people down etc. One day we were there, they let the dog out and she attacked my 2 year old.
We are no longer friends.