Here is what has worked for my son, who is also 7:
Heavy blankets or pillows on top of him – the weight is comforting. You could also try compression wear.
Meditation- we have the Meditation Studio app, which has meditations for kids. When he is having trouble sleeping, he now asks for a meditation, so it must help.
Sleep Training – same as you would for a toddler; stay in the room with him for gradually shorter amounts of time.
A loud fan or white noise machine
Audio books or soft music, set on a timer.
Deep breathing and thinking about his happy place
I hope this helps! Good Luck!