ROME (AFP) - Pope emeritus Benedict XVI is "slowly, serenely fading" but remains "very lucid", his personal secretary said in an interview published on Thursday.
Joseph Ratzinger is "an old man, of course, but very lucid. Unfortunately, it's become difficult for him to walk and he needs to use a walking frame," Georg Gaenswein said in an interview with the Italian magazine BenEssere.
In 2013, Benedict became the first head of the Catholic Church to resign in seven centuries, amid speculation he was on the verge of a nervous breakdown, unable to cope at the top of an institution beset by scandals.
He said he no longer had the strength of mind or body to carry on, but his health appeared to improve after he stepped down and moved into a former convent in the grounds of the Vatican.
"In April, Benedict XVI will be 89 years old. He's like a candle which is slowly, serenely fading. He is serene, at peace with God, himself and the world," said Gaenswein.
"He is interested in everything and still has his refined, subtle sense of humour. He still loves cats. Contessa and Zorro, two cats that live in our gardens, come often to say hello to the pope emeritus," he added.
Vatican spokesman Federico Lombardi told AFP "anyone can see he is becoming more fragile with time... he is clearly losing his strength."
While Benedict no longer writes books, the former pope known for his fine theological mind still dictates letters.
"He lives the life of a monk, but is by no means isolated: he prays, reads, listens to music, receives guests, plays the piano," said Gaenswein, who lives with Benedict and has revealed he plays Mozart on the piano from memory.
Pope Francis, 79, who was elected shortly after Benedict resigned, has said of the unusual situation of having two popes living so close to each other: "It is like having a grandfather - a wise grandfather - living at home."
Gaenswein, who still plays an active role in the Vatican and works for Francis as prefect of the papal household, said the current and former pontiffs were "very different in terms of character, personalities and way of communicating".
Francis "seeks direct contact, even physical contact", while Benedict "is more reserved. He caresses with words, rather than hugs".