would it be a risk if he rubbed his fluids possibly on the head of my penis?
From my understanding that is highly unlikely. The HIV would die to exposed air.
if his semen or possibly if he had blood in his hand touched the head of my penis?
even if it went in my urethra
HIV is unable to reproduce outside its living host (unlike many bacteria or fungi, which may do so under suitable conditions), except under laboratory conditions, therefore, it does not spread or maintain infectiousness outside its host.