Cloud died on Monday at age 25.
A source close to Angus Cloud's family tells ET the late actor "had been battling severe suicidal thoughts" ahead of his death on Monday.
"Angus had been battling severe suicidal thoughts after getting back from Ireland, where Angus and his family laid his father to rest," the source says. "Angus was staying with his family as he tried to work through overcoming the grief."
On July 14, Cloud posted a pic of his father smiling while holding out his pinky. In the shot, Cloud's dad wore an all-red sweat suit with the hood up.
"miss u breh," Cloud captioned the photo.
Cloud, who starred as Fezco on Euphoria, died on July 31, his family confirmed to ET. He was 25.
In their statement, Cloud's family noted that the actor had "struggled" in the wake of his father's funeral, which took place earlier this month.
"Last week he buried his father and intensely struggled with this loss," the statement read in part. "The only comfort we have is knowing Angus is now reunited with his dad, who was his best friend."
While Cloud's family didn't share his cause of death, they noted, "Angus was open about his battle with mental health and we hope that his passing can be a reminder to others that they are not alone and should not fight this on their own in silence."
"We hope the world remembers him for his humor, laughter and love for everyone," the statement concluded. "We ask for privacy at this time as we are still processing this devastating loss."
TMZ, who was first to publish the news of Cloud's death, reported that the Oakland Police Department and Fire Department responded to a 911 call made around 11:30 a.m. by the actor's mother.
She reported a "possible overdose" and said her son did not have a pulse, according to the outlet. The outlet additionally reported that Cloud was pronounced dead on the scene.
A source close to Angus' family tells ET, "Angus had been battling severe suicidal thoughts after getting back from Ireland, where Angus and his family laid his father to rest. Angus was staying with his family as he tried to work through overcoming the grief."
Meanwhile, in a statement to ET, an HBO spokesperson said, "We are incredibly saddened to learn of the passing of Angus Cloud. He was immensely talented and a beloved part of the HBO and Euphoria family. We extend our deepest condolences to his friends and family during this difficult time."