I would suggest that instead of having him try to "pass" as a genuine JW ( a task just a bit harder than getting an Aborigine to pretend to be an Eskimo), it would be far easier for him to pretend to be a seeker of truth who is convinced -- ABSOLUTELY, POSITIVELY, INCONTROVERTABLY, CONVINCED --that he has found IT.
Then he will have to submit to a free home Bible Study -- AND he will have to show signs of "making rapid progress in The Trooth," attending and participating at all meetings, etc., and continually "reaching out for additional privileges of service".
Only ONE of TWO things can go wrong --
1). He may actually become a witness after being so thoroughly BRAINWASHED,
--OR--
2) He may run screaming over the horizon, ne'er to be seen again!
Who says "Honesty is the best policy"?