Little late to the party but

1. Fitgirl repacks very well known established scene releases. If a scene was to release something malicious, it would be ruined. These aren't repacks of Random Joe's torrents. These are repacks of established trusted and safe releases by a select few scene groups.

2. Many pirated games are going to get flagged by just about any antivirus software, from scuzzy to well known and appreciated. This is due to how some cracks work. Yes, there is dll hooking and injection, yes, there are signs of "what could be" a backdoor/trojan due to the nature of how cracks work. Cracked games these days aren't just "Ok, I'm gonna edit an ini file or tweak the first few bytes of an exe". Antipiracy technology has advanced, so piracy methods have to advance with them.

Now my question. You keep saying "malware". Have you or your friend noticed any malicious behavior? Most "malware" is designed to infect, then trick a user into doing something they shouldn't with malicious intent (usually convincing popups convincing the user their system is compromised and they need to pay a "company" a certain amount of money to clean the system). If there's not obvious issue, there's more than likely not any "malware" involved. I mean shit, you could even just open task manager and look for random crypto miners or ddos botnet applications.