He’s her son. His mother, Em, lives with Bipolar Disorder.
Here he describes how he feels about the depressive phase of her illness.
I know that feeling.

“As if it were a wild animal with flecks of foam at its mouth, I feared her depression.

Imagine you were walking in a pleasant meadow with someone you love, your mother. It’s warm and there’s just enough of a breeze to cool you. You can smell earth and cut grass and something of a herb garden. Lunch is a happy memory in your stomach and dinner awaits you – a three course meal you have devised – all your comfort foods. The light is golden with a touch of blue, as if the sky were leaking.

Suddenly, your mother steps into a patch of quicksand. The world continues to be idyllic and inviting for you but your mother is being sucked into the centre of the earth. She makes it worse by smiling bravely, by telling you to go on, to leave her there, the man with the broken leg on the Arctic expedition who says ‘Come back for me, it’s my best chance, ’because the lie allows everyone to believe that they are not abandoning him to die.

Some part of you walks on and some part of you is frozen there, watching the spectacle. You want to stay but you must go. The imperium of the world’s timetable will allow you to break step and fall out for a while, but it will abandon you too if you linger too long by your mother, now a curled up foetal ball, moaning in pain, breathing only because her body forces her to.

Granny loved Em and she thought that should be enough. It wasn’t. Love is never enough. Madness is enough. It is complete, sufficient unto itself. You can only stand outside it, as a woman might stand outside a prison in which her lover is locked up. From time to time a well-loved face will peer out and love floods back. A scrap of cloth flutters and it becomes a sign and a code and a message and all that you want it to be. Then it vanishes and you are outside the dark tower again. At times, when I was young, I wanted to be inside the tower so I could understand what it was like. But I knew even then that I did not want to be a permanent resident of the tower. I wanted to visit but visiting meant nothing because you could always leave. You’re a tourist. She’s a resident.”

Source: ‘Em and the Big Hoom’ a profoundly moving book by Jerry Pinto, winner of the Crossword Book Award 2013.