This is actually mostly based on my own experiences with Estella Cigam and her little sister, Evelyn. They have the same age gap and relationship as the Holmes brothers. So, I'll begin.
The Holmes has an unusual family dynamic. For starters, Siger Holmes is a former Army man (I can't remember his rank, but it must've been pretty high) from an old money family. He's now a NATO official and married the equally wealthy Odette Holmes, nee Abney—she has a degree in psychology and dabbles in holistic healing.
I've never been to the Holmes manor and actually found normal processed foods.
Every piece of furniture has a story with it, and I've only heard half in all my years being a friend to them. Odd little trinkets—decorative ceramic boxes, rose-encrusted mirrors, ornate silver letter openers, little pig statues—and bottles of herbs dot every surface not dominated by books or collections of rare minerals.
Their first born was Mycroft Holmes, born with strawberry blonde hair that rapidly turned a dark ginger colour as he grew up. Mummy Holmes (when he's in trouble) and eight year old Sherlock called him Brolly. It sprang from his habit of—for hours on end, mind—sitting quite still, not speaking, with an umbrella when he was a child.
And he had an odd childhood—I've heard anecdotes where he's asked his father "What happens if you hang upside down for a long time?" and found himself hanging from the tree in the yard by his ankles. His father used to take him outside to play hide-and-seek-tag in the dark, and honed his son's night vision by randomly flickering lights on and off. As a baby, Mummy insists, he never cried much.
I believe it was eight years later (almost precisely) that Sherlock was born with a shock of dark curls that, in his baby pictures, at once set him apart from his older brother.
Sherlock had a full understand of English grammar and syntax when I met him—and he was scarcely five at the time, mind you. He also had this unnerving habit of noticing everything.
Mycroft had it too.
I met Mycroft Holmes when I eavesdropped on him and offered a suggestion for the conversation unthinkingly. Rather than grow annoyed, he thanked me for the contribution and asked me to join him and his friend Adair.
He was—and is—brilliant, and for that he can thank his parents: I don't know if genius is nature or nurture or a combination thereof, but they're responsible. Of course, they're also insane, the lot of them.
One morning I woke up in the guest bedroom (I'd stayed the night after helping Mycroft organise the herbs for his latest pet project, a study of poisons) to the following conversation:
"Pass me the pig cup?" Mrs. Holmes (this was before I started bursting into the Holmes manor and calling, "MYCROFT! Oh, hey Mummy, I'm home, where's Mycroft?") said quietly.
Sherlock was obviously in a bad mood, because he grumbled, "Why? You have a cup."
"Because," She replied patiently, "This pig cup is special. It is better to drink air from a pig cup than to drink juice from a regular cup."
Pigs. Don't get me started on the Holmes family and pigs. Pig stuffed animals in Sherlock's room; a pickled pig's heart on Mycroft's mantelpiece; little elegant statues in every imaginable art style; quotes on pigs; pictures of pigs; everyone in the family had a single favourite animal: pigs. They don't eat much pork, and I'm told the heart is from Mrs. Holmes's pet pig from Mycroft's childhood.
Don't get me wrong, I like pigs. But I like bacon better.
But back to my story!
Mycroft, on the day in question, rolled over and sighed at my mounting amusement. "You should hear about Santa Pig, the Easter Pig, and the Tooth Pig."
I lost control and started laughing, propping myself up on one arm and looking around the herb-smelling wreckage of the room. Mycroft had never had Mountain Dew before, so I'd made him drink a whole can. Needless to say, he'd been bouncing off the walls.
So enjoyable was the experience for my best friend that I had promised (under some duress) to buy him lots of caffeinated drinks for his birthday, and I even agreed to help him hide the contraband in his room and take credit if Mrs. Holmes found out.
She never did find out.
Look, Mycroft gets some bad press. Even if the press is banned from printing his name, I mean—in the quiet wraps of the British government, people talk about his coldness and unruly brother with a drug history. And I'll tell you a secret: he didn't want power. He still doesn't. But fact is, he's the best man—no, the only man—for the job.