Of course this is not legal advice.
No. The police can search your person for anything to keep themselves safe. Because he matched the initial description, they more than likely searched before having the witness say he did not match the description. Because they found drugs, he would have been put in jail anyway. I am sorry you paid so much bail, especially when your friend chose to carry an illegal substance. I would recommend seeking an attorney's advice, but more than likely, your friend will be best to take the deal and have probation and drug rehab as opposed to prison time.