I would say "to which" instead of "for which". Otherwise, it looks good to me.

I agree with Sharon, "to which" is more appropriate than "for which". I would probably add a comma after the date: "Since there was a delay in submitting the project, a reminder was sent to the student on 16th May 2019, to which he has not responded yet." It's important to note, here, that your date format is the British date format. The American equivalent would be "May 16, 2019" <-- the comma is necessary here.