The reason that I'm starting to remember what an ass the man is is that just as all the Pattersons really know about Thérèse Arsenault comes to them from biased sources, all we know about Molly and Gayle's mother is what a bloated oaf and the clingy, needy, malleable nitbrain he married tell us. It's like a foreshadowing of how Lizardbreath smugly palmed third- and fourth-hand gossip off on Candice as if it were the gospel. Given that Gayle spent the last few years of high school with this alleged negligent idiot and that both of them sought her out to help with their weddings instead of the pinhead squealing about ingratitude and heartache, my guess is that there is more than meets the eye here.
Let's also bear in mind that Greg is the jerk responsible for moving them to Milborough. The reason he gave is supported in the strip itself: simply put, indulging the little woman's need to have more ready access to her girlfriend Elly allowed him to put the barrier of at least five hundred miles between Molly and some innocuous drone of a B-grade rocker whose tastes in music and clothing terrified our boy. Given that most of why he kicked Lawrence out is that he labored under the lunatic misapprehension that Lawrence's being a straight gay would turn his tidy suburban home into a homophobic idiot's opium dream of a fantasy gay Hellworld, this might have been yet another over-reaction.
He bears yet another similarity to the Sainted Assthony: his need to throw the poor, dim woman he's married to under the bus. Like Pornstache would after him, he did so by exploiting Connie's innate stupidity and belief in miracles. The Liography and the strip made it quite clear that she (like Lizardbreath) believed then (and believes now) that the instant a new mother figure came into their lives, they should have been so grateful that they'd automatically love her to death and forget their birth mother. When this turned out to not be the case, the dough-head's reaction was to explode in rage and weeping and bullshit.
Since the poor, dumb woman was so heart-broken that two plus two equaled four, she didn't notice that she was being used as a lightning rod to protect Greg from absorbing complaints about his being a manipulative dick. It's like how Anthony uses Liz as a human shield when he wants to manipulate his own child. Remember "This is Daddy's girlfriend's ass. Kiss it or Santa won't come"? Same damned deal.
What Connie is right now tells us what Liz will be when she's sixty or so: a horribly ignorant woman who doesn't know that she's been used as a means for a gutless ape to mess with her step-daughter and can't figure out why the woman who 'rejected' her gets thought of more fondly that the woman who was 'there' for her. She'll also probably bleat about how she'll never get to be mother of the bride.