RIO DE JANEIRO (AFP) - His gentle voice in Girl From Ipanema still charms, but for Joao Gilberto, the sunny days of his bossa nova prime half a century ago have been replaced by financial ruin and family strife.

As one of the pillars of bossa nova, the breezy, melodious Brazilian style that took root in the 1950s and 1960s, Gilberto, now 86, earned his place in musical history.

But the romance and youthfulness of his most famous song about a head-turning beauty on Rio de Janeiro's Ipanema beach could not be more distant.

Short on funds, sick and living in a borrowed house in Rio, Gilberto is caught up in a family feud in which two of his children accuse his latest ex-wife Claudia Faissol, a journalist 40 years his junior, of exploiting the elderly artist.

And Gilberto's difficulties have been brewing for years.

"In his obsession to keep control over everything, Joao Gilberto wanted to stop the outside world so that he could focus on his art," Gilberto biographer Ruy Castro told Folha de S.Paulo newspaper.

"In front of the microphone he succeeded, but off stage it was the opposite: he had no control over his life. He got used to delegating to others." .

Obsessive perfectionism and eccentricity have long marked the singer of Desafinado, Corcovado and Chega De Saudade, which he often sang as a duet with his first wife Astrud Gilberto.

He is known for living in his pajamas and for reclusiveness, only opening the door of his home to get restaurant deliveries.

Bernardo Araujo, O Globo daily's music critic, said Gilberto's importance is "incalculable." "He was the principal voice of the best known Brazilian style in the world and a revolutionary without even really meaning to be," Araujo told AFP.

"He was the first singer, at least in Brazil, to demonstrate that you don't need a big voice, that you can sing quietly, like in a whisper, while accompanied by virtuoso guitar." But Gilberto had to juggle that smooth style with his demons.

"Like Michael Jackson or Prince, he's a wonderful and strange artist, but this strange side of him has taken him to today's terrible situation," Araujo said.

The man who along with composer Tom Jobim and poet Vinicius de Moraes put Brazilian music on the international map was declared legally incapacitated in 2017 at the request of his daughter Bebel, who like her brother Joao Marcelo is a musician.

"I wanted my father to have a happy, calm end to his life," the son told Veja magazine.

Since April, Gilberto has been living alone in housing said to have been loaned by Paula Lavigne, wife of another Brazilian musician Caetano Veloso. He was forced to leave his previous lodgings in the seaside Leblon neighbourhood because he had missed months' of rental payments.

Things really started going wrong back in 2011, when his wife Claudia persuaded him to go on tour to mark his 80th birthday and he then pulled out, citing health problems. He was ordered to return an advance of about $600,000.

Caught in a dispute with his first recording label, with no new album since 1989 and no public concert since 2008, Gilberto ended up having to sell 60 percent of his royalties on his first four albums to pay off the debts.

That deal prompted his children to accuse his now ex-wife of having tricked the artist in full knowledge that he was no longer capable of managing his affairs.

For most Brazilians, the last glimpse of the former star was a video in 2015 where he appeared in his customary pajamas and looking weak, playing Girl From Ipanema with his daughter Lulu, aged nine at the time.

It's a sad fate that Brazil's music community would love to see end on a higher note.

"Brazil owes a lot to Joao Gilberto and we have to find a way to help him," said agent Nizan Guanaes, who is trying to rally support.