I must have missed this part, well, "not your keys , not your bitcoin", I assume even if they were willing to help they would still charge him a certain amount pf fees, some exchanges will do that for a fixed amount like hitbtc charges $100 IIRC, some might ask for a certain percentage, and some will just tell you they can't do it, let's see how it goes for OP.
That's because it isn't cheap for them to get the private keys. That address might be in cold storage, for example. When they get the private key for that address they will expose the whole cold wallet and they will have to move all their coins (probably millions of dollars). There are many risks (like missing coins, messing seeds backups etc), costs (like mining fees and developers` time)
So, I doubt the website will give that private key for such a small amount...