If you put each { and } on its own line, and use Tools + Auto Format, you will see that you have this structure:
void loop()
{
if (mySerial.available() > 0)
{
int inByte = mySerial.read();
if(counter == 0) serByte = (byte)inByte;
// Snipped...
counter++;
if(counter == 2) counter = 0;
delay(15);
}
}
Now, what possible purpose is there for that delay?