I agree with Peg. He's anxious or frightened and uses itchy toe type reasons to be with you. Have you told him that you sympathize with his feelings whatever they are? He may not know what emotion he's feeling. You could tell him a story about another little boy who has the same difficulty as he does. Often, children will respond to stories about other kids when they're unable to express their own feelings. By listening to a story, your son may identify with the other boy. You could try telling the whole story and/or have your son finish the story. At some point ask him what would help the little boy in the story.
Both of my grandchildren go thru times when every little thing upsets them. I work on giving them more attention when they're not complaining and sort of "ho hum" the complaints. I sympatize, get a bandage, let them know I care about them in a brief, matter of fact way.
Mostly I'm with them in the day time or evening. They used to do this often during the night and still at times now. Their mother immediately puts them back to bed without responding to the complaint. She says, "you're OK. It's time to sleep, now."
If I were doing it, I'd also give them a hug but it's important
to spend as little time as possible with them. Instead focus on giving your son extra attention during the daytime, especially before bedtime.
Do you have a bedtime routine? Are you in the bathroom with him when he brushes his teeth? A warm bath and a story may help him relax and have something pleasant to focus on as he goes to sleep. I recommend spending around 30 minutes with both kids to include tucking them in, giving them hugs, answering questions about security issues if they initiate them.
My grandchildren like to have their bedroom door open and the hall light on. Their mother turns off the light and shuts their door when she goes to bed. They have a night light in their room, each their own stuffed animal to hold, and they take turns choosing what CD they want played once the "good nights" are over. This happens every night near the same time.
Before she tucks them in she asks if they've gone potty, had a drink of water etc. and sometimes reminded them that once they're in bed there is no getting "one more thing." All in a good natured, matter of fact tone of voice. "This is what we do."
Another idea about why he's waking up in the night is that he's had a bad dream. Perhaps he's had a dream that he can't remember but he feels anxious. So, during the day you could talk about dreams without asking him if he has bad dreams. Tell him about your dreams, good and bad ones. Say that sometimes you get scared when you have a dream. If he becomes part of the conversation you could gently ask him about his dreams.
I frequently don't remember my dreams and so I make up a story, appropriate for their age, around a dream I might have had.
I think the matter of fact and calm voice with as little time spent wirh during the night is important. He may have been anxious at first and now it's become routine.
Do your children have a chore chart on which they put stickers or make star marks when they've completed the chore. If so add sleep thru the night to the chart. Then he puts the sticker on the space when he does. Perhaps that will make it a routine.
I'm not in favor of bribing kids. It has backfired for me. My daughter would ask what she would get if she did such and such. I then started a routine of stamping in a small notebook. I bought a stamp of a package with a bow on it and she could stamp as many times as she wanted in the book any time she wanted to do so. I kept the book which insured that I was part of the stamping ceremony. This rewarded her and gave me an easy reminder to praise her and spend time with her when she was being good. All too often we are busy and end up mostly paying attention when our kids are acting out.
Is your bedroom close to his bedroom. You might try telling him to come to you if he's worried about something. Keep a stash of bandaids. When he comes in put on a bandaid for all complaints, give him a hug, tell him he's ok now and send him back to bed.
Remember that "this, too will pass." He's asking for more attention. Once he gets enough reassurance that he's OK he'll stop needing that time in the middle of the night. Reward daytime by giving him attention then. Down play night time when sleep is most important. It will take some time and patience to reverse this.
This message is way too long but I had a couple more ideas. Make being sure all of his body is OK before turning off the lights. Turn it into a giggly time. "now, does your eye itch" and playfully scratch about the eye. "how about this foot, is it OK?"
Another idea is to give him something to which he can talk when he wakes up. My granddaughter has always talked to her animals. Perhaps suggest to him that he tell your teddy bear that he's awake and his foot itches. Show him how the teddy bear can scratch his foot. Perhaps talk about the fact that teddy bear is always there and he can tell the bear anything and the bear will comfort him. Tell him that you'll check in with him and the teddy bear in the morning to see how the night went.