Corrie's wand was out, of course, but she didn't offer to light the room that way. Not after Ken's accident. At least not unless it was absolutely necessary - she'd rather save up her good spells and nonfailures to use against the boggart. She shook her head, then, realizing that he might not be able to see it in the darkness, said, "Sorry, no. Oh, wait... There's a little one on my keychain, I guess?" More of a laser pointer, actually. It emitted a green light that made her think of the Killing Curse, which was the main reason she rarely used it for anything but pointing at pictures of people she didn't like. But it had been a gift from friends, so she couldn't throw it away.
She pulled the light out of her pocket, keys jangling loudly in the dark and still house, and pointed it at Lorcan, trying not to feel squeamish about the faint, eerie green light that fell on him. "It's not very strong, but it's the best I've got," she said, adding "decent flashlight" to her mental list of useful things to buy. Just in case she found herself in anything even remotely resembling this situation again.
She held the light out to him, assuming that he'd want to use it if either of them did. If he wasn't doing any magic right now, it made the most sense to keep her free to do as much as necessary without distractions.