As sincerely stupid and rudimentary as his tard brain is, he's a natural born predator. His predator tard brain is adept at looking for and zeroing in on social contracts that he can use to manipulate what he wants from people. Unfortunately for him, his tard brain limits him from the subtlety and cleverness this requires and he ends up doing stupid shit like attempt to illegally blackmail his neighbors for a girl to assault, or constantly scream about Christians not doing everything he wants, based on his tard interpretation of what it means to be 'Christian-like'
His mom being involved with this whole complex with religion makes sense. I could see his mom attempting to wrangle his tard behavior with the fear of God/hell or instill rules of 'Christian' behavior, which I imagine was mostly about leaving people alone and the concept of sharing and waiting for your turn. Which to a special tardflake like Lucas, these very basic social rules must have felt exactly like enslavement to others.. and in his tard brain he formulated that Christians have committed to a life of doing 'good,' as in doing anything and everything for others. Of course this gets further cemented in his tard brain as churches have an open door policy and religious groups tend to focus on homelessness as a public service and he's spent the last decade+ stomping into churches, shelters, and soup kitchens with expectations of food and shelter for doing absolutely nothing, just on the merit of his putrid, piss soaked existence
In this vein of Lucas the predator, I could see both theories about his memory being true - that it's shitty and he genuinely doesn't remember his worst behaviors, and that he selectively and strategically doesn't remember his worst behaviors. Training your brain to ignore/not remember something and going through the motions on autopilot is a common phenomenon. I could see him choosing to forget or lying to himself enough to genuinely forget the truth for some things, and him doing his characteristic predator shit and feigning ignorance on other things, especially if its age of consent legal shit. Because if there's one thing a predator is going to be meticulous about, its going to be age of consent laws and the predator in Lucas overrides his defunct tard brain and I believe in this area, he's as lucid as can be, and that's why I think he's so dangerous and it's a matter of when...
EDIT:
holy shit this is the pic I was talking about!