It's hard to say for sure. To determine if Sergio is truly a factual account, one would need to look at the source material and the credibility of the information presented.
It's hard to say for sure. Sergio could be inspired by real-life incidents but could also be a completely made-up tale with no roots in reality. A lot depends on the author's intentions and creative process.
I'm not sure. It depends on the specific details of the story. Sometimes, elements might be inspired by real events, but it could also be entirely fictional.
Perhaps the 'the casagrandes never friending story' could be related to some past experiences that made them cautious about befriending others. It could be that they had been betrayed by friends in the past, so they are now more hesitant. Or it could be that their busy family life and all the responsibilities within the family leave them with little time to invest in making new friends.
Sort of. It takes elements from real-life situations and weaves them into a fictional narrative. So, it's not a strict retelling of a specific true story, but it has roots in reality.