Gotcha, Wotcha! But credit for your efforts to know what's going on in other-language cultures, not enough English-speakers do so.

The Brel family was involved in the decision to publish the songs on the occasion of the 25th anniversary.

Many artists are dissatisfied with some or all of their work and leave instructions that works are to be destroyed after their death. I don't think Brel went this far, I think it was rather that the songs weren't quite right yet at the time he died. After such a lapse of time, it's reasonable to publish them while making clear that he wasn't happy with them at the time of recording

If Kafka's wishes had been respected, he would probably never have become the household name which he now is.