I did not think it would be this soon, just after his fifth birthday, that his legs would finally fail him.
Bocketts Farm in Fetcham, Surrey, Saturday morning, and Theo stumbles over to me from the softplay on his toes, legs quivering below the knees. "I cannot walk, daddy! My legs hurt." With these words, he wraps his arms around my waist and holds on tight, through fear of collapsing in a sprawled heap on the floor.
I bend forward over his body, and reach for his calves, both of which feel more like small boulders than failing leg muscles. He relies on these like no other - as every Duchenne boy does - while he can still walk to keep him upright and moving forward. He's having contractures, his calve muscles shortening and cramping. I squeeze one of them, and feel him flinch with pain.
'I cannot bear this' is my immediate response as I lean back until I'm upright again, then look at him, my son, my dear son. "Daddy, I need to sit down," he says with extraordinary composure and pragmatism. I look around and cannot see a free chair anywhere. Now Oskar, his little brother, is here too, clinging to my leg and wants carrying as well. He might have Duchenne also, but unlike his older brother, he's definitely able to walk, simply doesn't want to.
Shit, what do I do? "I need a wee, daddy," Theo then utters. I carry them both, in either arm, to the toilet. Unable to stand, I hold Theo over the urinal while Oskar, out of my arms now, runs around inspecting every other vacant urinal.
"A chair, daddy, a chair," Theo declares, as I carry him out of the toilet and sit him down on the nearest one, then hurry back to get Oskar, who by this point has turned on every tap he can reach and is spraying and splashing water everywhere.
Back to Theo, with Oskar screaming under my arm - he did not appreciate his water show being interrupted - and Theo says, "A wheelchair, daddy, so we can look around," as if stating the obvious.
I burst into tears at this point, as a number of parents look on, unclear as to why this man before them with two adorable little boys is quite so upset. Oskar no longer cries, and Theo looks at me a little perplexed.
"Yes, a wheelchair," I mumble to myself, as I realise I've left Theo's at home and don't have a buggy either. Reception, yes, they might have one, I think, and hurry over to ask them. Bingo, they do, and Theo is suddenly delighted as daddy returns with a big red-framed one.
He's adamant that we look at the miniature farm exhibit, each window displaying a different season, then go and feed the animals: the goats, lamas, sheep and cows. Theo is smitten by an exceptionally greedy Billy goat, who proceeds to eat not only all the feed but the brown paper bag containing it, while Oskar is transfixed by a small Jersey cow, whose enormous wet tongue slathers his hands and arms until they are thick with saliva.
"Wash hands, boys," I insist, "then to the swimming pool". Will he be able to swim? I wonder. "Daddy, yes, swimming will help my legs," Theo says, as if possessing an innate understanding of his condition. "Yes, let's help those poorly muscles of yours," I reply, and he smiles warmly at me, excited to see Jo, his swimming instructor.
In the car and off we go, and before long we're there, at the pool, and Jo is waiting. She gets him moving in the water in no time, and soon he is walking again, the water seeming to seep into his legs and give them life once more.
I sit with my wife Klara, who consoles me, both of us watching Theo and Oskar through the glass, as I recount the events of the morning. And when I've finished, Klara, urging me to look at Theo laughing and smiling with Jo and his little brother in the water, whispers in my ear, "It is what it is, Nick, he is good within himself, and that is all that matters."
Klara is right, this is really all that matters, and yet I must still do what I can for him, I think, keep him on his feet for as long as possible before the disease takes its deadly grip.
Next week is The Big Bad Ride. Riding out with me are Nick Rucker, Dave Morrison, Joe Quigley, Chin Nicholson and Rob Dembrey, all the way from Land's End to London, just under 600km in four days. Thank you, gentlemen, for doing this. Please sponsor us here.