There’s no guideline. We all like to think that our relatives and friends don’t have to stay there long, but we really have no way of knowing short of getting some kind of private sign or revelation just for ourselves. When Padre Pio was on earth, people used to ask him if their dad was in heaven yet or whatever and he would tell them and then it was up to the person asking as to whether they chose to believe the “private revelation” answer.
A priest at a church I often visit said the other week from the pulpit that his own father had died 50 years ago that week, and the priest had been praying for his soul ever since and continued to do so. I have tried to do everything possible for my parents in the way of indulgences and Gregorian Masses, but it’s doubtful that I will get 100 percent clear knowledge of whether they have made it to heaven yet, although I have hope and have gotten one or two possible indications privately. I am currently praying a novena over this very subject.
On the bright side, St. Therese, who is a doctor of the Church, taught that one could skip Purgatory entirely if one trusted enough in the mercy of God, and Padre Pio told some folks that their loved ones had gone to heaven after a relatively short time.
