Damien
Over the course of a few episodes I would have Francis (living back at home) get a decent job and starts to become a big help around the house that pleases Hal and shocks and pleases Lois. At this point:
The entire family are asleep, we see shots of them all, finally seeing a shot of Francis, including his clock radio which says 1:57am. We hear a tapping sound and Francis wakes up. He gets out of bed and opens the curtains. A young man is standing there, long straggly hair, ripped jeans, Pearl Jam hoodie, chain around his neck. Francis looks highly surprised. He opens the window and lets the man in. At this point we find out that the guy's name is Damien and he went to school with Francis. He is essentially everything Francis was before he grew up. Damien and Francis haven't seen each other since Francis was shipped off to military school and now Damien needs a place to stay for the night.
We would then go to a shot of the morning in the Wilkerson house where Lois walks into the kitchen first thing and is horrified by the sight of Damien eating cereal at the table. We would then have a flashback sequence of assorted trouble Francis and Damien got into together when they were younger.
Damien always changes the subject when conversation starts to swing in the direction of why he needs somewhere to stay and how long he plans to stay. Over the course of two or three episodes we would see Damien continue to extend his visit, while Francis hastily becomes re-influenced by Damien and starts to ignore his responsibilities. Lois immediately thinks the worst and tells Hal that she knew it wouldn't last long and it was only to be expected that Francis would be a delinquent troublemaker again in no time. However, Hal has more faith and tries to calm Lois, saying how responsible Francis has been recently and that he hasn't seen Damien for years and as soon as Damien moves on Francis will be unproblematic once again.
Hal calms Lois for a period but when Damien gets Dewey drunk she snaps and in an emotional moment we find out that Damien has been kicked out of rehab for dealing and his parents refuse to let him stay there.
Hal and Francis feel bad for Damien and convince Lois to let him stay a little longer but after Damien steals Reese's girlfriend (who in a different plotline has been treating Reese badly) and tries to push marijuana to Malcolm, Francis kicks him out of the house himself.
At the end of the episode where Damien gets kicked out we would see Damien one last time getting out of a car with Reese's ex-girlfriend after hitch-hiking.
Damien: "See, babe, I told you everything would be fine. I grabbed Francis' wallet before he kicked me out of the house and I found this card. It says kitchen staff required, and this address. We'll just work here a few weeks, to earn enough money to get that plane to Hawaii, then we can move in with your multi-millionaire uncle, right?"
The girl nods and then the camera pans round to show the same place Francis worked at in Alaska. The slave-driving owner appears with two aprons.
"Welcome aboard. The aprons cost $30 a piece."