I did my PPL at Anglo in 3 weeks, my IR there in 2 weeks and my Airbus course in South Africa in less than a month. These things are possible but you need the right mental attitude and be prepared.
Treat your time not as a holiday, hit the ground running, and get into the studying. I treated the whole time as a course, that is I was at the flight school all day every day, I did loads of preparation and studying myself, had thorough briefings from the instructors and put the work in. Having a "can do" attitude will get you through.
If you know you are the sort of person who takes a few days to settle in, wants time off to rest or go sightseeing etc. then you ain't gonna do it in 3 weeks.
I found it a good way to learn, I did two flights a day, the second one consolidated some of the earlier lesson well and then we moved on to the next stuff.
Same with the IR.
It is possible if you want to do it.