My son is now 11 (so he's alittle older). Anyhow it was only up until about 18 months ago that he had to go in the room with me, then stand outside the stall where I could see his feet. That is if we were in places like WDW.
In March, we separated from DH & MIL a lot at the parks. So I was posed w/ this question once again. It was really hard. See I'd use the family room, tell him to turn his back and close his eyes. But he flat out refused!!!! So, we found restrooms that were in quiet locations and only had 1 entrance/exit. Then he'd go, while I waited. Then if I had to go-- I rushed!!! He waited right at the entrance. He was told to come in and scream loudly if anyone did anything. Poor kid, a CM could of said "HI" and he'd probably come running. It was nerve racking, but the choices were limited. I guess there just gets to be a point, that I have to allow him to grow up alittle, but like I said, he's a bit older than your son in question here. At 8 yrs old, he would of been coming in no doubt about it!!!