"They see each other at funerals and tragedies," a family friend says of the Kennedys

Caroline Kennedy, daughter of the late President John F. Kennedy, joined her relatives at a private wake and Mass on Sunday for 22-year-old Saoirse Kennedy Hill, a family friend tells PEOPLE.

Robert F. Kennedy‘s granddaughter and the only child of Courtney Kennedy Hill and Paul Hill, Saoirse died last week after a suspected overdose at the family’s storied estate in Massachusetts.

The multigenerational clan — the many different branches of the family tree, including the Lawfords and Shrivers, even the Schwarzeneggers (minus Arnold) — gathered Sunday evening at the home of matriarch Ethel Kennedy, 91, according to the family friend.

“They were all there,” the friend says. “The entire family was there.”

• For more on Saoirse Kennedy Hill’s young life and unexpected death, subscribe now to PEOPLE or pick up this week’s issue, on newsstands Friday.

“It’s sort of like a reunion,” the friend says. “It’s such a huge family …. [that] they see each other at funerals and tragedies.”

The friend says Caroline, 61, a former ambassador to Japan, gave one of the readings at the Mass.

“She looked very good,” the friend says. Caroline’s daughter Tatiana Schlossberg accompanied her.

Courtney, Saoirse’s mom, at one point assisted the priest with communion. “She has a visible, bad tremor …. but then she sort of rallied and she gave communion to all of her siblings,” says the family friend.

She also offered an intention. Quoting Courtney, the friend recalled it as: “For all the love that Paul and I had for each other, and for all the love Paul and I had for Saoirse.”

Caroline Kennedy
Saoirse Kennedy Hill (left) and Caroline Kennedy
| Credit: Facebook;Taylor Hill/FilmMagic
People Cover - 8/19/19 Dayton and El Paso Shootings
Saoirse Roisin Kennedy Hill
Mourners at Saoirse Kennedy Hill’s funeral Mass on Monday, including mom Courtney Kennedy Hill (second from left)
| Credit: DAVID L RYAN/Shutterstock

While emotions were more raw at Saoirse’s funeral service the following day, there was a close friend of hers who “cried and cried all during the Mass” on Sunday. The mood that night was “contemplative,” with a palpable grief yoking many of the mourners. But others were more stoic, and Saoirse herself was not often discussed by name.

The family is “just so used to public grieving, I think, that they do this in their own house but it’s almost as if they are expected to somehow be in the public eye and they have to be strong,” the friend tells PEOPLE.

In a statement last week soon after Saoirse’s death, the Kennedys said they were “shattered.”

“The world is a little less beautiful today,” Ethel said of her granddaughter.

In a statement to PEOPLE, Saoirse’s aunt Kerry Kennedy said, “These last few days have been abundant with suffering and love.”

Saoirse’s cause and manner of death — whether it was accidental — is pending a toxicology report. She was found unresponsive in Ethel’s home on Thursday afternoon after a late night on Wednesday that ended with a sunrise swim in the Atlantic Ocean on Thursday morning.

“Saoirse was the love of my life,” dad Paul said at her funeral on Monday, according to someone in attendance. “I loved her to death.”