Stranger Things' costume designer Kim Wilcox said Heaton was not pushed out at Netflix despite the drug bust because the show's creators value him and 'their family atmosphere.'
The award-winning designer said Heaton 'slipped' in his decision making and says that the 24-year-old English actor is a 'sensitive soul'.
"Charlie is returning," she said. "Charlie actually is one of my favourites of all the actors and I think he's a very sensitive soul. I think he's a good man and I think he's made some great decisions in his life and maybe this was just a time where something slipped."
She continued: "I think he's a fine actor and he's a great ensemble player and I think that in his work and in his presentation at Stranger Things 2, myself and to everyone else, he is very professional and an incredibly generous human being, so I don't see why they wouldn't invite him back."
Wilcox, speaking at the Costume Designers Guild Awards in Los Angeles on Tuesday, added that the show's creators, the Duffer Brothers, were instrumental in the success and family feel of the production.
That unity is what helped save Heaton, who dates his co-star Natalia Dyer, from the chop - as well as his successful plea to embassy officials not to be barred from entering the U.S. again.
She said: "The Duffers try and create this feeling of family and in large part, they succeed. You know we have all these children, we have their older siblings, we have their younger siblings, we have their dogs, we have their nannies, we have their parents, we have their teachers.
"It's a huge family and giant company, so I'm not surprised at all and I would have been surprised had they made a different decision."
Heaton's return is further aided by the fact that U.S. border officials will not press charges or take further action over being discovered with cocaine at the airport.
Insiders say Netflix has assurances from Heaton that he "would not let them down again", and that he met with U.S. Embassy officials in London. Filming starts in the next few days for the third run.
U.S. officers refused Charlie entry after discovering cocaine and he was sent back to the UK, missing the Hollywood premiere for the second season of Stranger Things.
A source connected to the show said: "Charlie is not being charged with any crime, and does not face legal action if he returns to the U.S."
They continued: "The Duffer Brothers and Netflix were very sympathetic to his plight. They have made it clear that he will have to stay out of trouble.
"His handlers have assured them that Charlie can overcome this hiccup and prove to them he does not have a substantial problem.
"There was sympathy for Charlie as they knew how much he loved the show, was a team player and felt bitterly disappointed at what happened."
After being sent back home following the incident, the young actor issued a statement, which read: "My planned travel to the U.S. last week was affected by an issue at U.S. immigration, and I am working to rectify it as soon as possible.
"I do want to clarify that I was not arrested or charged with a crime, and cooperated fully with the U.S. officials at LAX."
Fans have rallied behind Heaton, whose character Jonathan Byers finally hooked up with love interest Nancy, during the second series.
His mother and sister previously said a small amount of cocaine found its way on to his wallet at a party two weeks earlier, or at a bar or at a shop without his knowledge.
Family of the actor say he has never done drugs in the past and was not under the influence at the time he was stopped at the LA airport.
Heaton won the SAG Award for best supporting actor in a mini series last year and was a nominee this time.
Stranger Things is the 24-year-old's breakout role. He launched his TV career in 2015, appearing in British series such as DCI Banks, Vera and Casualty.
His big break into the American market came with Shut In, starring alongside Naomi Watts, Oliver Platt and Jacob Tremblay.
Before his foray into acting, Heaton was a musician, playing drums for rock band Comanech.
Costume designer Wilcox was nominated at the SAG awards, hosted by Gina Rodriguez at The Beverly Hilton in Beverly Hills.
The Costume Designers Guild, IATSE local 892, is a union formed for the promotion and protection of the art of costume design.
