What Causes White Patches In Mouth Along With Arm And Leg Numbness?

Hi, My brother is 34 years old and recently started seeing a dentist over a month age. He since than has had problems which include skin rashes, white patches in his mouth, arm and leg numbness, and some other ones. He has went to get a s.t.d. test to see if it what that but all tests came back negative. He went to the hospital and they said it was a bacterial infection and gave him antibiotics but they did no blood test or anything, just gave him the prescription. He feels there is something wrong and he does not go the doctors or hospital. Do you think he should get a 2nd opinion or continue with the antibiotics? He read on line that this could be dangerous if it is in his bloodstream? Please help, I don t want anything to happen to him.