Fine, not great, choppy, not perfect, if his clients want optimal colour accuracy or smooth panning or one of the other million things to consider when working in any type of 3D program, RDP is going to suck super hard. Fine is not OK.If they need to edit Word docs, I mean, sure it will work fine.+ it's fairly easy to set up and uses less BW when using H265 ;)
Edit: some software need better mouse support too, otherwise moving will have those spastic 5mil% movespeeds.
If they need tow work with 3D accelerated software, best not use RDP. Go for Parsec or similar. Parsec is free with paid plans for multiple monitors and more. It has been solid for gaming over internet when I travel with my laptop and is being used by teams at LTT for video editing.