If he believes it is getting worse, he needs to go to the E.R.
This is nothing to fool around with.
He may need a different antibiotic, he may need the area
debrided, or cleaned out.
If it is indeed MRSA, which stands for "Methicillin Resistant Staph Aureus"
it can spread quite quickly...
If he thinks it is worse take him to E.R. today.