Is that weird?

My SO works for a close female friend. They've known each other since high school and she made him the godfather to her son. I'm okay with all this, but she seems to have developed some sort of unusual emotional and social reliance on my SO, which seems a little weird to me. For example, when she was pregnant with her son she insisted my SO go to most of her prenatal visits with her, even though she has a husband. She insists that my SO attend her father's birthday birthday. She insists my SO attend her husband's birthday party. She tried to get my SO to attend her husband's niece's birthday party. Her husband doesn't think it's weird at all that he is at basically every single family function of theirs, even though they rarely attend his. It just seems odd to me.