Splitting Heirs (1992)

When the Duke of Bournemouth dies and leaves his entire estate and businesses to an American called Henry (Rick Moranis), whom he thinks is his son who was lost as a baby and then found again all hell breaks loose.

Then there's an Englishman, Tommy Patel (Eric Idle) who thinks he is an Indian (he has been brought up in a Pakistani community and thinks this is where he belongs) and then comes to believe that he is actually the heir to this fortune.

Now Tommy comes to hate Henry, who is his boss, his friend, and the man who has stolen the woman after whom he lusts.