Welcome to the site !!
I am wondering , did he drop/crash it hard on the shifter side ???? , if so , it is "possible" that one of the shift forks (in the tranny) is bent , not saying that is the issue , though a lot more detail would help , I am assuming that since its a 17 , that it is used ??? , if so , any history on it ??? (dealership trade in ?? , Private Party kid outgrew it ??) , or is it a "new" leftover ??? (if so it should have some sort of warranty)
But more detail is needed on the backstory behind the shifting issue , since it sounds like every other gear is not a issue , but details in knowing if it was crashed on that side , etc. , and it shifted fine before the crash , etc. , or has it done this since it was purchased ?? , As much info as possible would help diagnose possible causes , as there is any number of things it "could" be , but you have left out a lot of important info in your description .......