Baby name choice causing family split
What are your thoughts on a mother choosing for her new baby the abbreviated form of a name already given to her cousin's one year old younger son? Let's call them 'Brad' and 'Bradley'. She had no wish to copy but had other reasons for choosing the name Brad. Should she have sought her cousin's approval before naming her baby?
In this case her cousin, my stepson, is outraged and the issue is causing a big problem in our family. He sent her a very curt congratulatory email with a pointed reference to the name similarity. Her baby is only 2 days old and now, in the midst of her happy glow, she is hurt.
Unfortunately we are unwillingly caught in the middle and in trying to gently diffuse the situation have been angrily and unfairly accused by my stepson of inflaming it! I should add that he himself chose a name 6 years earlier, let's say 'Michael', that in it's abbreviated form, 'Mike', was already in use several times in our family. Ironically this included the firstborn of his other cousin who my stepson never consulted before naming his own son. The family, including Mike's mother have never taken issue with his choice.
I am not sure there is any way that this can be resolved other than by my stepson's temper cooling over time (knowing his nature I will not hold my breath) but he will almost certainly sever the relationship between himself and his cousin, which is especially sad as their two firstborn sons adore each other. I also fear he will punish us by restricting our relationship with our grandchildren 'Michael' and 'Bradley' who are very dear to us.
I would be grateful for your thoughts.