Need Opinions Please

Some info on us.

I am married and have a step daughter. My younger brother is married, she had 2 children and they have 2 together. My youngest brother is divorced.

I wanted to get a portrait of my brothers and 2 nephews together for my mother for Mothers Day. I have to book the photographer I want by January 1st.

I send my brothers a text telling them what I wanted to do, that I will pay for it, I just need them to verbally commit so I can book the session.

My youngest brother sends the message " Im in, let me knoe when and where"

My other brother sends us the message, "That sounds like a good idea but it will cause problems at home if her 2 kids cant be in the picture, so we cant do it."

That was a direct quote.

My youngest brother and I just dont understand the problem.

My brother will not get a portrait done because children who are not my mothers grandchildren.. children who treat my mother like shit, are disrespectful, and sure as shit do not see my mother as their grandmother.. can not be in the picture.

I spoke with my husband because I just didnt get it. He said that it doesnt make any sense. Its not like we are excluding only her kids, adding my step daughter and our spouses in the picture. He said that her being pissed that her 2 kids are not in the picture is like him being pissed that his daughter is not in the picture. It is pointless.

Do any of you think that I am being unreasonable, by wanting my brothers and my nephews and myself to have a picture that we can give to my mother? Am I being unreasonable that I am not including 2 children who have no real connection with her? My stepdaughter said that she gets it, especially since I got a portrait of her and my husband, by themselves, done for my mother inlaw.

I am trying to drop it, but I just cant get over the fact that my brother is allowing her to just lay down the law and he is folding to it, without even a discussion.

It is ultimately screwing my mother because she cant have any pictures of just her grandchildren. All pictures that have them in it has to have the other 2... but the other 2 children can have pictures taken with their father and my brothers chikdren are not allowed in them.

I just am having a hard time not being angry with my brother.

Please, if you dont agree or understand where I am coming from, say is respectfully... I am really in no mood for rude answers.

Thank You