First of all I just want to say this. If I were Sam, I would just tell everyone my dog is dying. If my classmates laugh at that, then I wouldn’t have any respect for them. Sam shouldn’t be ashamed of caring for his dog.
Sam’s lie impacted his mother’s and father’s life in a positive way by making their neighbours and people in their community empathy/pity them. When they heard Sam’s dad was dying, they felt like it was right to try and comfort them with their company, kind words/compliments, and homemade lasagna. Before, his mom and dad were either overly stressed and overly depressed. Sam feared he couldn’t cheer them up anymore but with the neighbours suddenly caring for them, they feel appreciated. To Sam, his lie let him get away with ginormous ice cream scoops along with his classmates now knowing about what really happened with his dog. I don’t think the lie was worth the consequences because the effects of it won’t last forever. After everyone knows his dad wasn’t really dying, they’ll go back to their normal life, not giving any more attention to their family, maybe even less than before because then they’ve known they were all being lied to. The situation was fake but everyone believed it and gave their feelings to Sam’s family. If I were to find out it was all a lie, I would be irate at them. Including the fact that he used that pity to get more for himself. The ice cream girl would have a grudge on him from then on because she thought she was doing the right thing, giving more to Sam since he was suffering but she was just being tricked the whole time.