If they fly AI in Business Class, you can rest assured that they will be treated very well. I could write a book about the service they will experience on AI 102/112, but I don't think you are really looking for what the menu will be or which movies are showing.
The seat pitch is a comfortable 48" and the Business Class cabin is located on the upper deck of the B747-437. The food is excellent and there are 18 kinds of special meals available ranging from Kosher to Gujarati.
Check-in at JFK will be smooth since there are 2 seperate desks for the F/J class pax, so they will not have to stand in the regular line that stretches all the way down to Jersey. The Maharaja lounge is located on the 3rd floor of the Air India check-in area and they can relax over there until flight time. The lounge is in serious need of renovation though, but it is definitely preferable to sitting out in the terminal. At flight time, one of the staff will escort all the F/J class pax to the aircraft and allow them to board seperately from the crowd. Its a very smooth operation.
Transit at LHR will be equally smooth. Depending on whether the flight is assigned a jetway or a remote parking bay, pax will be asked to disembark. They can choose to stick around in the transit area by the gate or they can head over to the Maharaja lounge which is located by Gate 1 near the duty-free area. I reccomend the latter, because the lounge is very comfortable and the staff there are very friendly and helpful. Additionally, the Eastbound flight can arrive about 40 mins ahead of schedule, so the LHR layover can be upto 2.5hrs long.
Arrival at BOM can be somewhat of a zoo, but if you drop me an email with your travel dates, I will try to have a special handling message sent to take care of them. Even without that though, there should be a ground crew member assigned to assist F/J class passengers and escort them through priority immigration clearance. Their checked luggage will be PRIORITY tagged at JFK and should already be on the belt by the time they clear immigration. Terminal II-C isn't particularly crowded at 11pm when AI 102 arrives (all the Euro carriers begin arriving about an hour later - and then also to Terminal II-A), so customs should be a breeze as well.
"The A340-300 may boast a long range, but the A340 is underpowered" -- Robert Milton, CEO - Air Canada