
Neither the teats nor vulva go back to pre-pubescent discreet size after the first season so it may be the size she is now is what will be normal for this bitch from now on.
However if the teats appear to be filling up with possible milk rather than slightly more prominent nipples only, then it could be she is having a phantom. If she is having a phantom it is best that anything she becomes attached too - such as toys - are removed from her to prevent her brooding over them. Her exercise should be stepped up and add some further mental stimulation to her daily routine to "take her mind off things" and disengage her maternal instincts.
Your friend's vet should be able to advise if it is an actual phantom or not. There are meds which can be given if it is proving very problematic but, although fortunately my girls have never gone through this, I personally would prefer to avoid meds unless it was genuinely in the dog's best interests.
HTH, Teri :)