That's what we like to hear, Mani. Driving out devils ! Hasn't been done in ages ! Of course, your friend could be bisexual and not 'cured' , as you might say, by exorcising demons.
He wouldn't be the first married, or female partnered, homosexual either, whatever you may think. There have been many, throughout history.Some had relationships with lesbian women,perhaps, but a great many were, so far as can be told, married to 'straight' women. A goodly number sired children. Even today, in Britain, there are those who are constrained by their faith, their community, fears for their public image or other factors,including, of course simple privacy, to keep their homosexual feelings private. Some other people would never understand them, they themselves may feel guilty, or fearful of the ignorant opinions of others [why, if they read posts on this site?], we can't guess what the reasons of an individual are in such matters.
And they can't be 'cured', though it's understandable, given the above, that some might want to be.