SAS Script understand or optimize

I have a critical SAS script that was left from the person before me in my position. the data has gotten massive and the script takes a millinium to run. I dont know SAS but I'm quite good in other languages mainly R. the operations this code does has a simple output but when I try to figure out what exactly is happening in the script I get lost. I need someone who is really good in SAS to basically optimize the code or translate it to me to be done in R.