Help: RPM drops with AC on

What parts/components maintain/increase the rpm when you turn on the AC? For the last couple weeks, my son’s car no longer did this. Anytime he turned on the AC, the rpm will drop and the engine is at borderline to stall. Vaccum leak somewhere? Thanks

The RPMs will always drop with the A/C on because the Compressor is activated which is run by a belt and pull of the engine.

The RPM should drop immediately when the comoressor is activated, then come back up to normal. The Helms specifies the same idle with or without A/C on. This might be the IACV not working right - there are teg tips for checking and cleaning it.