Jimmy Carter is still "emotionally engaged" as he approaches his 100th birthday

He told People magazine: "I mean he's been in hospice for over 19 months now and he has really physically diminished and can't do much on his own.

"But he is emotionally engaged and still having experiences and laughing, loving."

In June, Jason admitted there had "really been no change" in Jimmy's condition since he went into hospice in his native Plains, Georgia.

In November last year, Jimmy's wife and former First Lady Rosalynn Carter died aged 96.

Speaking to Southern Living, Jason said his grandfather was "experiencing the world as best he can as he continues through this process".

He added: "After 77 years of marriage... I just think none of us really understand what it's like for him right now.

"We have to embrace that fact, that there's things about the spirit that you just can't understand."

Although Jimmy isn't awake every day now, his family still visit frequently.

Jason recalled one visit earlier in the year when he asked his grandfather how he was getting on.

He said: "I told him, I said: 'Pawpaw, you know, when people ask me how you're doing I say, 'honestly I don't know'.

"And he kind of smiled and he said 'I don't know, myself.' It was pretty sweet."

Rosalynn died last year, months after being diagnosed with cancer.

At the time, President Joe Biden and his wife Dr Jill Biden said in a joint statement: "She was a champion for equal rights and opportunities for women and girls; an advocate for mental health and wellness for every person; and a supporter of the often unseen and uncompensated caregivers of our children, aging loved ones, and people with disabilities.

"Time and time again, during the more than four decades of our friendship - through rigors of campaigns, through the darkness of deep and profound loss - we always felt the hope, warmth, and optimism of Rosalynn Carter. She will always be in our hearts."