VPN cant install in other CPU when other account is logged in? Or how to do it?

Hi, I just bought VPN premium license for 10 devices, it worked well on my CPU, then I tried to install VPN on my father's CPU, but when i did it, his Bitdefender Antivirus went off because my BD account was activated on his PC, but not only for VPN app BUT ALSO REPLACED his account on his BD antivirus (my Antivirus License has no room for more CPUs...)... then I had to reactivate his Antivirus with his account, but then the VPN got deactivated again! it seems that you cant have two BD products in the same computer under 2 accounts?

Is there a way that i can install VPN premium in other devices that have BD Antivirus logged in with a different account vs mine?