If you had told me five years ago that I would have to change my mother’s diaper, I would have hyperventilated at the mere thought. The reality of doing it, when it became necessary, was actually surprisingly straightforward. The same applies to most aspects of caring for a loved one. The things that seemed impossible in theory are made possible by love. It is as if a limitless battery of affection has been charged by 40 years of her looking out for me; and now that the reverse is needed, a splendidly efficient autopilot system has engaged.

I share the responsibility of looking after her with my sisters. To say I am her part-time carer would not be accurate. I am, rather, her full-time carer some of the time. Every couple of months, when I fly back to her to do my “shift”, the terror of the possibility she might not recognise me looms large. I have to actively stop my mind from running forward. First, because Alzheimer’s is not a smooth downward curve, but a jagged downward line – she has good days and bad days, just like everyone else. If she is confused today, she might be much less so tomorrow. Second, because I know now that the imagined reaction to a horrible hypothetical is always more dramatic than the actual reaction to the real.

I realise another thing, too. As someone who hasn’t raised children I find the process exciting and rewarding – is that OK to say? Practicality takes over. Routine becomes the balm of anxiety. There is an enormous amount of washing and cleaning and ironing and planning and shopping and cooking, and a little crying and mostly anticipating need or danger. I have never had someone depend on me so completely.

Offering unconditional love is a pleasure I had quite forgotten in the cynicism of my 40s. Of course, I would give anything to have her dementia disappear. But it can’t and so I make the most of the situation as it is. It has taught me more about myself and the world than any single situation before. It is a juggling act that we make up together as we go along. I am raising my mother in reverse, and that is as challenging, fulfilling and impossible to prepare for as it sounds.

We pan together for gold on a daily basis, and while we empty pail after pail of frustrating sand, the occasional nugget is more than enough to sustain us. She can still experience sudden, merciless moments of absolute clarity. Sometimes they manifest as angry shards of the woman trapped somewhere inside, piercing through the fog of pharmaceutical oblivion, threatening or pleading. On other occasions it is like my beautiful mother of 10 years ago has come to visit for a morning, have a cuppa, see how I’m doing and thank me for looking after her.

Three weeks ago I was in the land of make-believe, singing and dancing on a London stage. This morning I stood in the shower, fully clothed, washing my mother, naked and sobbing, after she had an accidental bowel movement. It is as big an adjustment as I will ever have to make, I think. To borrow a line from one of her favourite films: “When you’re a secretary in a brewery, it’s pretty hard to make-believe you’re anything else. Everything is beer.” All I am, when I am with her, is her son. Nothing more, nothing less. I am the supporting actor of her Act III; she the protagonist of my Act II. Life is inescapable and also deeply tender.

I am always surprised when people say “you’re so brave” or “I don’t know how you manage it”. We have looked after our young, our sick and our elderly for millennia – much longer than we’ve had currencies or composed symphonies, or even believed in deities. What I am doing is, in actual fact, entirely ordinary. All that was required was to disengage my overactive, self-obsessed, 21st-century brain and allow it to happen. It is what is in our DNA: love and compassion – not selfishness, not envy, not hate, not a desire for profit. When the time comes and one has to step up, that much becomes crystal clear.

Tomorrow is the end of National Alzheimer’s Disease Awareness Month and National Caregiver Month. We must talk about it. We must share our stories, without shame. Sharing our stories is therapy for the individual carer and support for others in a similar position. It helps develop a collective understanding and a body of coping strategies. This year alone in the UK an estimated 116,000 people will have to leave or significantly adjust work in order to care for someone with dementia. To be silent, to hide our elderly people away, is to condemn millions to the joyless torpor of merely awaiting death in isolation.

There are still gold nuggets to be found in the deepest, thickest sludge. Don’t miss them by looking too far back or too far forward.