"Simon is exactly as you would expect someone to be who has just lost the woman he loved. Some days he wants to kill himself, and other days he seems to be coping better," Monjack's mother Linda, a hypnotherapist and counselor in Buckinghamshire, England, tells PEOPLE. "He is distraught. I speak to him everyday, and he is often in tears."
But thanks to his bond with his mother-in-law, the London-born businessman, 39, is surviving, his mother says: "He's very strong, and he's got Sharon. They're very close, and they're keeping each other going."
A Tight UnitMurphy and her mother were "extraordinarily close," Murphy once told PEOPLE. "She's my earthbound angel."
Even after Murphy and Monjack married in April 2007, Sharon continued to live with her daughter in their Hollywood Hills home.
And quickly, says Linda, the three became a tight unit.
"Sharon witnessed [Simon and Murphy's] love," she says. "She was so happy her daughter had found someone."
And Monjack and Murphy's feelings were real, she continues: "They truly loved each other. I don't think they ever spent more than a few days apart. They were going to start a family this year."
Desperate for AnswersSince Murphy's Dec. 21 autopsy, coroner's office officials are currently awaiting toxicology results that could help them determine the actress's cause of death.
Monjack "is waiting like everyone else for the report from the coroner," a family friend says, "but he anticipates the cause of death will be from natural causes."
In the meantime, Linda says her son is struggling to grasp what could've happened.
"I spoke to them both the day before she died, and everything sounded normal and fine." she says. "It was a three-way conversation, with her laughing and talking to me in the background. Her voice was gravelly because she was recovering from laryngitis, but she seemed in good spirits.
"The next day, when she'd died and he got back from the hospital, I spoke to him, and he was in total and utter shock. I could hear Sharon crying in the background. It was heartbreaking."
"He didn't want the autopsy [in the beginning]," she went on, "for the reason that anybody wouldn't want his nearest and dearest to be cut open. He realized pretty quickly that he had to agree to it, and he's waiting for the results. He wants to know what happened."
For now, all her loved ones can do is wait.
"Simon's life has been shattered," says Linda. "He needs closure to be able to get on with it."
With reporting by HOWARD BREUER, KEN LEE and MONIQUE JESSEN