Dream Letter is the name of a song on Tim Buckley's 1969 album Happy Sad (and, incidentally, a live album posthumously released of a 1968 concert played by Tim in London). It's one of only two songs in Buckley's entire catalogue that are obviously addressed to his son Jeff Buckley, the other being 'I Never Asked to be Your Mountain'.
Tim and Jeff only properly met once several years after the release of this song, and Dream Letter serves as Tim's woeful yearning to be with his son - ending with the haunting "oh, what I'd give to hold him". Reportedly, Jeff's mother Mary Guibert was angered by hearing this song on the radio, believing that if Tim really wanted to see Jeff, he wouldn't have left her.
Jeff, who hated being seen as 'Tim's son' in his own musical career seemingly - remarkably - replies to the song with his own song 'Dream Brother', the last track on the only album released in his lifetime, 'Grace'. The song was inspired by Jeff pleading a friend of his not to leave his pregnant partner, as Tim did - "don't be like the one who made me so old / don't be like the one who left behind his name." 'Dream Letter' followed by 'Dream Brother' is worth a listen; an emotional letter from a father to his son, and the son's response, decades later.