David Crosby thinks the death of his biological son was a "test"

Responding to one Twitter user who described him as a "donor who played no part" in raising Beckett, he replied: "Not true."

A fan then sent a message of condolence over Beckett's death.

They wrote: "While I know that you were a surrogate, I also know that you just lost a son. I'm sorry, I know you've had a rough year."

David replied: "Maybe it's a test."

The veteran singer no longer has a relationship with his former Crosby, Stills, Nash and Young bandmates Stephen Stills, Graham Nash and Neil Young and he isn't expecting them to reach out following Beckett's passing.

One fan wrote: "Wonder if even one of the CSN&Y guys will reach out to you regarding the loss of Beckett. Sure would hope that all have enough class and respect to do so. But won't hold my breath.(sic)"

David replied: "I doubt it but ...you never know (sic)"

Melissa has admitted her "heart is broken" following her son's death, which she attributed to his addiction struggle.

She wrote in a statement on Twitter: "Today I joined the hundreds of thousands of families who have lost loved ones to opioid addiction. My son Beckett, who was just 21, struggled to overcome his addiction and finally succumbed to it today

"He will be missed by those who loved him, his family and friends. My heart is broken."

The 58-year-old singer also thanked those who have sent their condolences to the family, and admitted she's glad her son is "out of the pain now".

She wrote: "I am grateful for those who have reached out with condolences and I feel their love and sincere grief.

"We struggle with what else we could have done to save him, and in the end we know he is out of the pain now.

"I will sing again, soon. It has always healed me."