Jen Aniston Scared Sick About Her Father's Ailing Health

Just a few months after the death of her mom, Jennifer Aniston is worried sick about losing her dad.

"John is way less mobile than he used to be, and Jen's concerned about him," a source told RadarOnline.com of 83-year-old soap opera legend, John Aniston.

"He spends most of his time outside of Los Angeles these days and that means Jen finds it difficult to see him because of her busy schedule."

As RadarOnline.com reported, unlike the unfortunate physical distance from her beloved father, Jen purposely kept as far as she could from her estranged mom, Nancy Dow, who died last May at the age of 79.

"Jen's tried inviting John to stay with her and her husband," 45-year-old actor Justin Theroux, "in LA, but he's not in a position to travel much so she has to make do largely with phone calls."

Still, Jen, 47, refuses to always accept her pop's excuses.

"She wants to spend Thanksgiving and Christmas with her dad," explained the source. "She adores him and is desperate to treasure every last moment they have together."