Since the SCP Foundation involves a lot of dark and often inappropriate content, it's hard to define 'key elements' in a positive way. But if we assume a more positive take, maybe the old man's age and the wisdom that comes with it could be a key element. His appearance, perhaps with a long white beard and wrinkled face, might also be characteristic.
The SCP series often contains disturbing and inappropriate content. However, if we consider a more general 'old man' story in a non - SCP inappropriate context, it could be about an old man with a lot of wisdom and experiences. Maybe he has seen the town grow and change over the years, and he likes to share his memories with the younger generation.
I recommend "Stay With Me For The Rest Of My Life", a modern romance novel about wealthy families, to you. Similar to "My Uncle Yule," this novel also had a plot where the female protagonist pursued a handsome uncle, and it was also a 1v1. In the novel, the female protagonist misunderstood that her "savior" had become the daughter of his entire family, and thus began her journey of "coaxing her uncle". I hope you like this fairy's recommendation. Muah ~😗
The SCP Foundation is purely fictional. It's a collection of imaginative and often creepy stories and characters that are made up for entertainment purposes and have no basis in reality.