Yeah and from my personal experience, Myrna is a fucking raging nutjob, too.
As everyone knows, mental illness runs in families. Its not a coincidence they're all mental. I'd bet money that he inherited most of his crazy from myrna and she knows it (and we know she knows it because shes talking about being medicated several times), which is why she made up a crackpot, physically impossible story about how lucas supposedly became crazy. Notice how lucas also makes up crazy stories to explain away things he wants to hide. Notice how myrna has the same deflection reaction to being confronted with lucas's behavior as lucas himself does when he's called on it. Gee, I wonder where he learned that
As for lucas himself, the older he gets the worse his health gets and the worse his mental health and sanity deteriorate. Even medicated as he is now its clear he's aggressive and seething and that the medication is barely keeping a lid on his behavior. It used to be that lucas had at least some degree of self awareness, as even he recognized he had mental problems and should have been committed when he was screaming at cars and such. Now he refuses to acknowledge there is anything wrong with him or his behavior at all, and much of the time doesn't even accept he's mentally ill at all. Sooner or later the meds won't work effectively enough and it'll keep him from being able to stay in shelters or other facilities and he'll end up a screaming nutcase, either permanently locked up in the nuthouse, jail or wallowing in his own filth in the woods or under a bridge. Though I suspect the later will inevitably lead to the nuthouse or jail eventually
To put it simply, lucas is living on borrowed time. He is only ever going to get worse mentally and physically. What he has now is the best he'll ever have it. Its all downhill from here. He better enjoy a roof over his head and food while it lasts
and when things inevitably get bad enough that he's at a very real risk of dying of exposure or poor health I wouldn't put it past him to decide he's fucked anyway and go after an underage girl, figuring at worst he has nothing to lose and will end up in jail with a roof over his head, medical care and food if he gets caught. He might even think he can pull an insanity defense and get committed instead, and get back to the nuthouse that he's used to living in anyway and get all those snacks they give the medicated.
When lucas starts to see the psych ward and jail as a valid out and determines he has nothing to lose, thats when he'll become overtly dangerous. He already has the mentality for it, the only thing keeping him in check is the fear that he has something to lose if he gets caught. and even that doesn't keep him from doing illegal shit whenever he thinks he can get away with it