RDP attack from Mac on home network

Hi folks , I looking for advice.

My sons MacBook Air is connected to our home network. I have Avast running on the main PC laptop which has reported continued Remote access attempts sourced from the IP address of the Mac Air book

I have scanned both computers for viruses/malware (using avast). but nothing shows up.

Additionally checked the Remote access settings on both machines and seem to be turned off.

Only thing we have knowingly done is log my sons icloud account prior to the notifications appearing.

anyone got any advice?

macbook air, early 2015 model, high Sierra 10.13.6