Regarding server downtime;
If this IS a DDoS related attack, your best bet is to try and enable router black-holing, or call the VPS company themselves and ask what options you have to prevent further attacks. (Most of them have VERY good protection)
If this is NOT DDoS related, then it could be way easier than the coder/manager may seem to think.
Regardless, this should not be that difficult to eliminate whatever issue is creating the downtime.