Spell Checker

So I have a client who hates GW because the spell checker (according to him) is awful.
He wants one that understands names and local spelling of things and ideally wants the ability to import a lot of words he uses all the time in bulk.
I suggested this functionality would never come and he has asked me to investigate integration of a third party tool like Grammarly. I think he would even consider something that sat resident in memory and went over the top of all his apps including groupwise.

Does anyone else do this or know of any app that could relieve his "misery"?