I feel if she was attending regular therapy, the impulsive behaviour would be curbed slightly. Speaking to a therapist/counsellor would give her pause for thought. It's easier to disregard what family or friends might be telling you, because you're close to them, and have probably heard it all before.
Sometimes you need an outside party to hold the mirror up to you (this is coming from someone who attends regular therapy, it's a god send if you can afford it).
The kids come across very happy, the little dotes. Lindsay is a good mum, and I'd imagine they're shielded from a lot of what goes on. But, as they get older, they'll cotton on to how dysfunctional Lindsay can be. I'd say the young lad is already becoming aware of it.
I reckon Jenny is starting to distance herself a little bit from Lindsay's personal life; only so many times you can support someone before you realise you need to focus on yourself. You'd be driven cracked watching a friend repeat the same mistakes over and over again. It'd take a toll on any friendship.