Sounds like a lousy company with lousy bosses. Dunno what they are doing. It is as easy as how much you are willing to pay for that person.

If company is willing and can afford only, as example, 5k then offer 5k la. Be direct to the point. How much he got during previous job is none of your business.

Why you need other company pay to dictate how much you should pay. Have a spine.