Simmons remained in the hospital until Monday.
Estey delivered a message following the fitness icon's hospital stay, according to USA Today.
"Thank you to everyone who has reached out with love and concern after hearing I was in the hospital. I was dehydrated and needed some fluids and now I am feeling great! Summer is here — drink plenty of liquids. Big hugs and kisses for caring."
Estey responded to an email from USA Today inquiring about Simmons, saying, "He's just fine."
— USA TODAY (@USATODAY) June 6, 2016
Simmons has been living as a "virtual recluse" over the past three years. He told Entertainment Tonight that he was merely looking for solitude.
"I love all the people who worry about me. But it was time for me to take some time to be by myself. For the last 40 years I have been traveling, teaching classes, and I had a knee injury, so I had a knee replacement, which was very difficult for me... I have really just been taking it easy, staying at home, working out in my gym and doing the things I haven't done in a very long time."
Estey responded to rumors at that time that Richard was being held in his Hollywood home against his will by his caretaker, who was performing black magic on him. Estey called the story "ludicrous" and defended the star's right to his privacy.
"It's his right to do it. That's the god's honest truth. There's nothing more to it than that."
Simmons personal assistant at that time was 49-year-old Mauro Oliveira, according to College Candy. Oliveira claimed that in April 2014, Simmons had a mental breakdown after one of his dalmatians died.
"He got completely messed up. He was already having some breakdown, some mental breakdown, some problems with anger management, some falling outs. I believe it is a culmination of a lifetime. Because he's always been high on life for his whole life and I think it finally crashed down."
The dalmatian, who was named Hattie, was 17 when she died several days following Richard's last public sighting.
Known for his signature look of a flamboyant tank top and gym shorts, Simmons has helped millions of people lose weight with his unconventional aerobics routines.
As Earnthenecklace points out, he was also popular as a guest star with comedians "thanks to [his] comical way of addressing the audience and his over-excited behavior."