During my time Instructing I came to the conclusion there were three kinds of Students. Those with outstanding natural flying ability (only a very small number), those who picked it up with Instruction (most people) and those who were just never ever going to get it (again a VERY small number). Someone needs to sit down and have a frank discussion with this poor guy.
With hundreds of student names in the logbook I only encountered one person who just couldn't and would never have made a competent pilot. It might be brutual but honesty is the best policy. They have to know the truth.