The star is planning a memorial service for his father and helping the family "plow through" this difficult time, a source tells PEOPLE exclusively
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Robin Thicke‘s world was shaken when his father and beloved TV icon Alan Thicke died suddenly on Tuesday, but the star is soldiering through to help his loved ones during this difficult time.

“He’s been a rock for the family,” a source close to the star — who has two brothers, Carter, 19, and Brennan, 41 — tells PEOPLE exclusively. “Carter is obviously still very dazed and so is their other brother. Robin is the one taking the lead and organizing everything with Alan’s wife Tanya.”

Currently planning a private memorial service and party for early next week, Robin, 39, is also organizing a memorial fund with the family to help raise money for finding a cure for childhood juvenile diabetes (a cause close to his father’s heart), according to the source.

“He’s been spearheading all of this and remained strong and is keeping the focus to help the family plow through this,” says the source.

The Growing Pains star died Tuesday at 69 years old after suffering a heart attack while playing hockey with Carter. Robin, whose mother is Alan’s ex-wife Gloria Loring, remembered his father as “the greatest man I ever met” in an emotional interview with the Los Angeles Times. “I saw him a few days ago and told him how much I loved and respected him,” he told the newspaper.

“My Father passed away today,” he later wrote on Instagram. “He was the best man I ever knew. The best friend I ever had. Let’s all rejoice and celebrate the joy he brought to every room he was in. We love you Alan Thicke. Thank you for your love. Love, your grateful son.”