Was she in the wrong to say that to her child?

**I am going to use fake names and not disclose my identity or relation to each person to make it as objective as possible. I’m neither of the mothers, I’m just somewhat involved as I know both. The dynamics may cause some confusion so I will apologize for that in advance.**

So a woman, Kelsey, is married to a man. This man’s brother got a woman, Jackie, pregnant. Kelsey was pregnant around the same time. They each have daughters who are a couple months apart. The cousins are friends and see each other often, but sometimes get in little arguments. They are 11. Jackie has a few other children with other men and doesn’t stay in relationships long. She has the personality where she likes to brag and if she feels insecure about something, she’ll just hype it up and try and make those she’s envious of feel less than. She teachers her children to be kind of similar. But anyways, she is in a relationship currently and has been with him for three months. She has her children refer to him as their dad. Well Jackie’s daughter was bragging to Kelsey’s daughter that she has two dads and therefore is better. Kelsey’s daughter got upset about it and told her mom. Her mom said something along the lines of “she has two dads but the second won’t stick around for long” and explained that there’s nothing wrong with having only one father. The next time the girls got together, Kelsey’s daughter that her second dad wouldn’t stick around for long. Obviously this upset the girl and she told her mother. This caused a large argument between the mothers. So was she in the wrong?