I am sorry that this has kicked off again 
A couple of points to consider:-
This dog is NOT aggressive - an aggressive dog would have bitten. This dog did not bite.
This is a dog that has considerable self control (maybe more than some of the posters on this tread
)
The dog was in his opinion in a very scary place and he warned his owners that he was uncomfortable.
They are now counter conditioning the dog to the baby and if this is continued for as long as the dogs needs it the dog will have no need to feel threatened and there will be no need to growl.
If the dog was aggressive then there would be a different response from the knowledgeable dog experts on this thread.
The OP is not putting her dog before her DC but is very sensible taking expert advice (not hysterical overreaction from non dog qualified people on a forum)
Let us know how things progress OP