How we cite our quotes: All quotations are from Home Alone.
Quote #4
KEVIN: No offense, aren't you too old to be afraid?
MARLEY: You can be too old for a lot of things, but you're never too old to be afraid.
Kevin has to get over his own fear of the burglars—and Marley has to get over his fear: he has to meet with his estranged son and heal his family. They both help put things in perspective for each other, and Marley points out that fear isn't just for kids, but something you have to deal with throughout your life.
Quote #5
KEVIN: I've always been afraid of our basement. It's dark, there's weird stuff down there, and it smells funny; that sort of thing. It's bothered me for years.
MARLEY: Basements are like that.
KEVIN: I made myself go down to do some laundry, and I found out it's not so bad. All this time I've been worried about it, but if you turn on the lights, it's no big deal.
Kevin suggests, through analogy, that if Marley will go into his own metaphorical basement and deal with his own metaphorical furnace (the issue he has with his son), he'll find that the problems he's dealing with aren't really so implacable.
Quote #6
KEVIN: My point is: you should call your son.
MARLEY: What if he won't talk to me?
KEVIN: At least you'll know. Then you could stop worrying about it. Then you won't have to be afraid anymore. I don't care how mad I was, I'd talk to my dad. Especially around the holidays.
With his simple wisdom, Kevin convinces Old Man Marley to speak to his son again. (We see them reconciling later in the movie). Our worries and fears magnify our problems out of proportion, and the idea of confronting a problem is scarier than actually confronting it.