All professional healthcare providers exclude pre-existing conditions, as to take these clients on increases company risk for an almost inevitable payout and then increases premiums for other policy holders. It does of course depend on what the pre-existing condition is - you may get denied completely, have it excluded, accepted with loading or be issued with a moratorium period of time.
I've only recently started dealing with them but their credentials seem very solid indeed. If you put it through my company I will be happy to rebate something...
BUPA International are highly regarded in the UK. They operate internationally too but their service is not so good in this market. There are comparable (and slightly cheaper) options available to him - William Russell, VUMI, LUMA... If you can email me his date of birth I will get some comparisons for you.
