I have a friend who is planning a trip to Puerto Rico from JFK.

JFK > SJU

He is a large individual and will need to purchase 3 seats and pretty much sit in the middle seat.

he had a question and I couldn't find an answer on delta.com.

IF he buys 3 seats for himself, does he earn MQM and MQD for each seat? Will each seat get 1 segment.

Or will Delta consider the 3 tickets as 1 Ticket, where he will earn MQM for the miles flown plus MQD for the total of the 3 tickets and 1 segment?

He was actually considering going by boat but he was told that could take up to a week to get there. Didn't even know this was possible.