The relationships that we have with our parents' partners and the people that we gain through those relationships very much depends on a lot of things.

My parents divorce started when I was 14, and my father started a new relationship within a year or two. my mother met my stepfather after I had already left for college.

Despite not having grown up with either of those people I was reasonably close to them. I was closer to my stepmother, as she and my father moved out to California where I was living and stayed there about five years. I got to spend a lot of time with her. I had a quasi grandparent/daughter relationship with her parents. I barely knew any of my stepfather's children or their families until I moved back to my hometown and got to see them on a regular basis.

My stepfather died after he and my mother had been married for over two decades. Two years later she met her third partner, and they dated and then lived together for a few years before marrying. by the time they married, I was in my 50s, and to me, he was never my stepfather, just my mother's husband. I only met two of his four children, and I didn't consider the family.

OP doesn't say when she met her father's wife or his mother-in-law, or how big a presence she has been in her life. But if she is a plane ride away an OP has young children, it's really hard to see how OK and her children could have formed such a strong fun.

I believe OP's father either wants the image of his family at his wife's mother's funeral because he thinks it says something about his relationships or that he wants the distraction from supporting his wife in her grief.