Your friend is correct; it's a Paramount. The giveaway is the distinctive rear seat tube bend introduced in 1975 on the T-19/22 models. It's hard to know the year from these photos as the frame has been repainted and the components look to have been updated. A ballpark guess would be '76 - '79 but a check of the serial number on the left rear drop-out will provide the definitive answer.
As for value, what ever someone is willing to pay.... perhaps a couple hundred bucks because the paint and parts are no longer original??
However, be forewarned, the forks on these tandems were not designed for tandems and the '79 model year forks may have had a manufacturing flaw that made them more prone to failure than previous years. Ron Templin experienced one of these first hand 'back in the day' that is mentioned in a article in the archives at his
www.secondsummertours.com web site. A thorough inspection of the fork crown area would be warranted before purchase and periodically thereafter if the tandem was acquired and ridden.