Hashian, the drummer for the rock group Boston, is also the father of Johnson's long-time girlfriend, Lauren Hashian.
According to his son Adama, Sib was on the Legends of Rock cruise that left Florida on March 18 and was mid-set when he collapsed on Wednesday night.
According to a witness, CPR was performed, and a defibrillator was used, but Sib's life could not be saved.
Dwayne, also known as 'The Rock,' reportedly left the Las Vegas set of HBO's The Ballers, to be at Laura's side immediately he received the news of Sib's death.
On Thursday, Dwayne posted a long and touching tribute on Instagram with a family photo.
"Rest in peace & love to my second love Sib Hashian," Dwayne posted on Instagram, adding that he does not understand why things happen the way they do when loved ones leave us without having a chance to say goodbye.
"What a full and exciting life this man lived. What an amazing family he created, loved, watched over and protected," Dwayne went on to say in his Instagram post.
Meanwhile, the partnership between HBO and Dwayne Johnson takes off on Monday when 'Rock and a Hard Place,' a documentary produced by the former wrestler, airs on the channel.
The documentary follows jailed juveniles looking to cash in on a second chance, as they attempt to conquer the Miami-Dade Country Corrections and Rehabilitation Boot Camp.