Tucker was such a cute old man, Danny thought. He thought it every time he saw his friend's wizened form, which was at least once a week. His friend had lost most of his hair, and his face was covered in wrinkles, but the smile and laugh lines were the deepest, showing the good and fulfilling life Tucker had led.
Not that Tucker could remember that life, or even who Danny was. But he was usually happy to see Danny anyway. Danny wished he could have gotten old alongside his friend, maybe be staying in Amity Park Care Center with him, able to play Doomed 42 with him every day and watch his friend flirt outrageously with the nurses that were 60 years younger than him.
But Danny had never aged. He still looked like a 14 year old, whether in human or ghost form. Jazz had told the staff that he was Tucker's grandson. Hmm, maybe having to call Tucker "Grandpa" when the staff were in the room was contributing to his confusion over who the heck Danny was...
That, and the lack of Sam. Her and Danny had been glued to each other's side for the past 70 or so years. She'd passed last year. Cancer. Danny had hoped to reunite with her ghost, but he wasn't surprised when a ghostly Samantha Manson never turned up. Although she'd have enjoyed being a supernatural creature, she, like Tucker, had led an extremely accomplished and happy life, and passed to the other side with no regrets.
Danny was usually happy too, surrounded by children and grandchildren that loved him and helped keep his immortality a secret, kept him sane as he watched everyone he knew slowly disappear over the years, lost to illnesses and accidents and just the passing of time.
There were dark spots sometimes though, nights where he couldn't sleep and was overcome by his fears. That he would truly live forever and watch everyone around him die through the ages, eventually giving up on loving anyone since being attached hurt. And his deepest fear, that he couldn't speak even to himself—that he'd never again see Sam or his parents or anyone else he loved. He tried to console himself with the scientific facts. At the very least, the sun would burn out one day, the planet would end, and surely that would destroy him, let him cross over. He'd see her then.