The One With Phoebe's Cookies - S7-E3
Corrected entry: When Jack, Monica's father, is telling Chandler about when he first met his wife's parents, he says that they still think he is a lawyer to this day, and that if Chandler sees Jack giving them legal advice he should play along. The problem is, at least one of them is dead, having passed away in The One Where Nana Dies Twice (in which episode there was no sign or mention of Nana's husband, or since, so I would guess he had already passed on). She was definitely Judy's mother, not his. (00:18:50)
Correction: Jack makes mention of his 'in-laws', in conjunction with saying he told Judy's father he was a lawyer. The implication is that despite her parents now being dead, Judy's family as a whole still thinks he's a lawyer.
Ral0618