Alcohol & Drugs: MIP, MIC, Intoxication What is Minor possess ?

[idahoan]

My son was camping with several people. 3 of them were in a tent. and approx. 15 in a cabin, and a few in thier cars. There was Two parents there and on private property. The Sheriff show up, they were asked to leave the private property. and didnt. They immediately asked for my son . Who was sleeping in the tent. they woke him up by flash light, told those three to go back to sleep, then later came back into the tent and arrested only 2 of the 3 in the tent for minor possess. There were empty beer cans in the tent. and they all blew a 0.00 at the station, now he has a ticket minor possess, but they have No proof of it. How does he plead? what do we do when we go to court? do we need an attorney? this is his first ticket, he is 16 and he has been harrassed on several occasions and I as a Mom is fed up with it! they also searched his vehicle with out him knowing it. The parent saw them search it. What are our rights to fight this? I would appreciate any help.