A: So sorry to hear of your loss--the loss of a child must be even more poignant than the loss of a spouse.
May I offer an interpretation of Urantia Book teachings? Although not so specifically stated, it can be interpreted that children are inescapably linked to the mind currents of both parents from the moment of conception until they reach an age of self-determination, which is about 16, and from that point on they become true individuals. They also receive their Thought Adjuster, their contact with the Holy Spirit, connection with the Spirit of Truth, and the birth of their soul at about age 6. Outward appearances don't indicate what is going on within the mind and soul of any individual whether child or adult.
It's also my interpretation that it requires extraordinary effort here to make sure that one doesn't arrive at the mansion worlds--I believe the major sorting occurs there after the deficiencies we live with here have been corrected and only then an informed decision about personal survival can be made.
As for myself, I have no concern or worry whether I will arrive on Mansion World One three days after I die here or whether it happens at the next dispensation, however long that takes. We're not in a race, it's a process where time is no longer of any consequence. So I'd be just as happy being a sleeping survivor as I would to be resurrected on the third day--the time lapse will seem to be the same in either case to my perceptions.
So, my answer for you would be that there is no way for us here to determine who survives or doesn't--the decision is wholly between God and the individual despite our own wishes and intentions.
But I also think it is safe to say that you will one day be able to reunite with your son for a time in the worlds beyond this one. Remember—nothing of value is ever lost—and relationships are the thing of highest value that we do here. So, that scaffolding has been established, and I feel sure that you will be able to build upon it someday."