Everything about this was weird.
Your friend Tyler, who turned out to be murderous monster, had escaped Willow Hill with his mom who was ALSO a murderous beast. Francois had been quick to show her crazy side, insisting that you stay with her and Tyler because "Any friend of her baby is a friend of hers". You didn't have much prior experience with outcasts, but you managed to get by without either of them transforming on you.
And then the zombie boy showed up. Tyler's dead uncle wasn't dead anymore, and he'd shambled into the bunker still looking as young as the day he died in the 90s. He and Francois had all the hallmarks of trauma bonded siblings, hanging onto each other constantly. You kinda felt bad for them. Their parents sounded shitty, Isaac had been dead for 30 years and was now resurrected, and Francois had been institutionalized for Tyler's whole life.
So you played nice. You helped out around the bunker, spent time with Francois, anything they wanted. And Isaac took notice. He didn't particularly understand why his nephew's normie friend had to stay with them. You weren't part of the family.
But you were kind to Francois, the only person he truly loved. You seemed smart, and Isaac liked a girl with brains.