The veteran yacht captain and reality TV personality took to Instagram on Monday to share the tragic news in a somber post dedicated to his late child.
"This past Saturday, my beloved wife Mary Anne and I laid our youngest son, Joshua Lee Rosbach to rest. After a twenty year struggle, he finally succumbed to the demons he fought so long and so hard," Lee wrote in a caption alongside a smiling photo of Joshua.
"Addiction is an insidious disease that knows no social status or geographic boundaries," the distraught father continued. "Whether you live in a 10,000 sq ft mansion or a double wide trailer, the path of death, destruction and devastation it leaves remains the same."
Lee wrote that "in spite of his problems," he loved his son "unconditionally," and that Joshua was a man who selflessly devoted his life and energy to those he cared for.
"There was no one I ever knew who gave more of himself to those in his life. He loved with all his being without expecting anything in return," Lee wrote. "We both feel a hole in our souls that will never be filled."
Ultimately, Lee said he has a message for everyone who is fighting the disease of addiction, or knows someone who is: "Find a way to get help no matter what."
"For those of you who have a friend, family member, son, or daughter who's struggling, do what ever it takes to get them the help they need. Be kind and loving, and try to enjoy every second you have with them," Lee concluded. "Do not pray for our son, but please take care of your children and friends who may need it, as it isn’t too late for them."
"At the time of his passing he was in the hearts and minds of those he loved the most," the tribute shared. "A gentle and kind soul, Josh was loved by everyone he came into contact with and never met a stranger."