I don't think this doctor understands what re-birthing is. Does he say not to give the baby a bath until the immunizations are through? BTW, I have seen a seven week old take to the experience successfully.
I have noticed, even without the bath component, many babies, when lying belly-to-belly nuzzle their way towards the breast of the person holding them.
Even when we are all clothed. A few babies I have seen do this were exclusively bottle fed, and not responding from habit, but from nature.
Sincerely, Chanita