change of course at same HEI

This question is for my friend:

He has tier 4 visa till Dec 2017 but he changed a course at the same HEI.

This course is a year shorter than he had given permission before.

I understand that tier 4 policy guidance mention that if course is shorter than migrant must report to MigrantReporting@homeoffice.gsi.gov.uk

but his HEI said don't worry we already inform UKVI so you don't need to inform it.

1. My question is what would be the result of telling UKVI?
2. Also my friend changed the course 4 months ago but he still didn't send the email would that effect his further application in
the UK?

if the university has reported the change den don't need to worry about.