Where I instruct there is a student that is working towards his instrument rating. He will be on his 6th grad ride flight very soon. What you should ask yourself is if you really want and student/pilot that ends up like this. It doesn't matter if he could get through the rest of the flight all that matters is that he cannot make the cut. The student where I work every flight, descends below MDA/DA no matter what and then cannot track an NDB, I haven't flown one in years anyways but is never mentally there. If it comes to a head you are putting your certificate on the line saying that he can fly. I agree though, there are some people that think just because they flew 3 years ago that they still know how to put the aircraft where they need it to be.