He cites Fisher's "Star Wars" fame and their clashing personalities as reasons for their struggles.
Disney said Fisher's role would be gleaned from 'The Force Awakens'
Fisher passed away in December, having finished shooting for 'The Last Jedi'
The Star Wars actor was rushed to hospital on December 23 after collapsing on a flight from London
Significance of heart disease, drug addiction in relation to her demise had not been ascertained
Carrie finished the shooting of Star Wars: The Last Jedi before her death on December 27 last year
Debbie Reynolds and Carrie Fisher, who died in December just a day apart, were remembered by fans and friends
Fisher appeared in four 'Star Wars' films and returned in 2015's 'The Force Awakens'
'She said she really wanted to be with Carrie and within 30 minutes, she was gone'
The 84-year-old suffered a stroke at here son's home