I wish I could help, but I came on here to ask about a similar situation so I do empathise and cheekily piggybacking on this thread to see what advice others have.
My son, also 7, used to lie in bed having a little sing song to himself before happily falling asleep. Generally sleeping through the night - sometimes waking up earlier than I'd like him to but apart from that, all good. I mean, occasional bad dreams and nighttime anxiety but all manageable.
I think the catalyst was one of his older friends (9) telling him some dreadful urban legend that scared the wits out of him and gave him bad dreams. That was months ago now and he's now scared of being on his own in bed and won't go to sleep without me sitting in his room, which can take anything between 5 minutes to 45 minutes. Then, invariably, he will wake up in the night and not be able to go back to sleep and come and sleep in our bed, which we were letting him do on occasions when he had a bad dream, but now it's getting to the point where he comes in nearly every night and becoming a habit. I've tried taking him back to his bed, which means I have to sit with him until he goes back to sleep, which then means I can't get back to sleep for hours. Mind you, when he comes in my bed I get a very bad night's sleep and can barely function the next day anyway so, either way, I'm ragged the next day! Just to add an extra layer of fun, when he's in my bed it "activates" the cat, who comes in, walking all over me, meowing, and then my son sits up and strokes him. It's chaos! Then he wakes me up every 10 mins or so from 6am to ask me if it's morning yet. FML!
I tried playing a kids' sleep meditation to help him get to sleep but he just stayed awake listening to it and I think we got through about four of them in a row before I gave them up as a bad idea.