One possible theme could be loyalty. If the father's best friend has been around for a long time, loyalty within their friendship and perhaps loyalty to the family as well. For example, if the family faces some difficulties, the friend might show loyalty by helping them out.
He may be very generous. Whether it's with his time, sharing his knowledge or resources, a generous friend is a great friend. He might be the kind of person who is always willing to help others without expecting anything in return, and that's why he and your father are such good friends.
One possible theme could be forbidden love. Since it involves a relationship with the father of a best friend, it's likely to be a relationship that society might not approve of.
The main themes in 'My best friend's husband novel' could be complex relationships, self - discovery, and moral dilemmas. Complex relationships are obvious as it involves the relationship between the best friend and the husband. Self - discovery might come into play as the characters might have to figure out who they really are in the face of such a complicated situation. Moral dilemmas are also central, as the characters have to decide what is right and wrong when it comes to their feelings and actions towards their friends and their friends' partners.
It might be about their adventures when they were young. For example, going to the beach and having a great time.
One major challenge could be social stigma. People in society may still hold prejudiced views and this could lead to him being ostracized or treated differently. Another is legal issues in some areas where gay rights are not fully protected, like in terms of inheritance or visitation rights if he has a partner.
Maybe the father is an author of the novel. He could have written it based on his own experiences or the family's stories, which might involve my best friend in some way.
I'm not sure as I haven't read that specific novel. It could be about a complex relationship between the narrator, their best friend, and the friend's father. Maybe it involves some secrets or life - changing events related to the father figure.
I'm afraid I have no idea about the author. It could be an indie author or someone relatively unknown. You might need to do some research in book databases or libraries to find out.
Friendship is also a big theme. It shows how the relationship with the best friend can be tested when there are romantic feelings for her brother. It might also explore themes of loyalty and betrayal in the context of friendship. For example, if the protagonist starts a relationship with the brother without telling the best friend, it can lead to a lot of drama. Another aspect could be self - discovery. The main character may learn a lot about themselves, their desires, and what they are willing to risk in the process of getting involved with the brother.
Friendship is an obvious one. It shows how characters interact, support, and grow with their friends. For example, in many novels, friends help each other through difficult times.