What is Virginia law regarding probable cause search of a minor child?

My son and a friend of his were pulled over in Stafford County as they were walking home from summer school, the deputy claimed he stopped them because they didn't cross the street at the light and they were impeding traffic, he then proceeded to tell them that the Wawa on Garrisonville that they had cut throught the parking lot of on their way home was a known area for drug dealing. He then asked them if they had any weapons or drugs on them and they told him no, he proceeded to keep asking them several times and they continued to tell him no. He then said well do you mind if I search you and the boy with my son gave him permission to search him (apparently this boy had been in trouble before) my son however told him no, but said I will take the things out of my pockets and show you but you cannot search me because I didn't do anything wrong, nor do I have anything illegal on me. The deputy proceeded to tell him that he was acting stupid and dumb and that because he was acting that way that gave him the right to search him. He made him put his hands on the hood of the car and he told him to put his hands behind his back and put his palms together, (my son has a limp because one leg is shorter than the other and he already has had one surgery on the leg). It was kind of difficult to get his palms together because of the height problem so the deputy accused him of trying to escape and handcuffed him, he then ran his name through the system and then he let him go.