Case length and shoulder length 100% agree with and recommended to him earlier. His problem is it not fitting and there were no marks on the marker test, I can't see how those measurements would help.No.
If you measure the case length, the shoulder length, the base and shoulder diameters of a fired and sized case the problem becomes immediately apparent. Casting the chamber is not required.
If he had some case head separation, bulging or any type of marks on the brass with marker those measurements would be needed but none of that is his problem.
Edit: I'm curious what you are looking to compare the diameter measurements to.