Dennis Hopper's wife said in US court documents that she believes the actor is divorcing her because of his declining health and influence from others.
Victoria Hopper wrote that her husband's medical and mental state became unpredictable as he battles prostate cancer, according to the documents filed in Los Angeles Superior Court.
The 42-year-old is seeking full custody of their six-year-old daughter.
She is also asking a judge to allow Dennis Hopper supervised visits with his daughter for up to an hour per day, depending on his health.
Her filing seeks strict guidelines, including a requirement that Hopper remove all guns from the family's house and refrain from smoking medicinal marijuana before the visits.
"I do not believe that petitioner is capable of taking care of himself or his legal and financial affairs," Mrs Hopper's declaration said.
"Therefore, I do not believe Petitioner is capable of making sound decisions in the best interests of our daughter."