He might be angry at first. Naruto has grown up alone and had to fight for acceptance. So when his parents say they regret abandoning him, he could lash out, saying it's too late. After all, he has already faced so much without them.
The son could ask for some time and space if he feels too overwhelmed in the moment. Then, when he's ready, he can sit down with his parents and have a proper conversation. He can also share some educational resources about homosexuality with his parents to help them understand better.
In some fanfictions, Naruto may become extremely bitter. He could feel a deep sense of betrayal and this might fuel his determination to become stronger, not for the sake of the village at first, but more for self - vindication. He might isolate himself from others and struggle with his identity.
Their friends would react in different ways. Lee would be extremely enthusiastic, seeing the new life as a symbol of new hope and strength. He might offer to train the baby when it grows up. Tenten could be practical and offer to help Temari with any baby - related gear, like making or finding the best crib. Neji, if he were still alive, would be more reserved but still offer his congratulations and support, perhaps by using his Byakugan to check on the baby's health from time to time in a non - invasive way.
Choji would probably be super excited. He's their close friend and would likely offer to cook all kinds of delicious and healthy food for Ino during her pregnancy. Naruto might be a bit clumsy at first but would be very enthusiastic, offering to do any odd jobs they need. Sakura, being a medical ninja, would be very practical, giving Ino regular check - ups and advice on how to stay healthy. And Kakashi might give Shikamaru some father - to - be advice in his laid - back but wise way.
Sakura might be a bit surprised at first, but then she would be happy for Naruto. She has always been his friend and would see that he is happy with Shikamaru. Kakashi would probably be very supportive. He has seen both Naruto and Shikamaru grow up and would understand their connection. Sasuke, on the other hand, might not show much emotion on the surface, but deep down he would be okay with it as long as Naruto is happy.
In some versions of the fanfic, Harry might have a sort of instinctive understanding that his parents had a good reason for leaving him there. So, while he's still not happy about it, he might be a bit more accepting. Maybe he can sense some sort of protection spell around the Dursleys' house that gives him a small sense of security.
I recommend "The Peasant Daughter-in-law". The female protagonist of this book also raised a child alone, while the male protagonist was the eldest young master of a peasant family. The plot also involved the situation where the female lead avoided certain people in order to protect her child. The entire novel was set in business and farming, telling the story of how the female protagonist started her own career and found true love. I hope you like my recommendation, Mwah~
Some adults may feel extremely humiliated. They are no longer children and being spanked makes them feel as if their parents don't respect their adulthood. For example, they might become withdrawn and avoid family interactions for a while.
One possible reason could be that Naruto has some sort of power within him that they fear. Maybe it's a power that they don't understand and think could be dangerous, so they hate him out of fear.