In general, it's safest to leave people's parenting choices uncommented on, even the choices they make before the kid has left the womb.
While it can be painful to watch a slow train wreck in real time, people really don't like unsolicited advice from family members, even if the family member is right.
They wrote:
AITA for telling my sister she needs to name her baby like he will grow up and not give him a "cool" baby name?
My sister is obsessed with the show Yellowstone. Her husband is willing to do anything to make her happy. They want to name their baby Cowboy. I know I should have kept my mouth shut. It's not my circus or my monkey. I just know the absolute sh*t that kid will go through.