When you make your name getting overheated at trivial things, what’s left when life issues deadly serious challenges? Rhod Gilbert was six years away from standup before his current show – six gruelling years, by the sounds of things, during which his mum died, he had a stroke, and struggled with infertility. He looks those experiences straight in the eye in The Book of John, but finds a way to make them uproariously funny by bouncing them all off the apparently gormless chauffeur who ferries him between these adventures in humiliation and personal disaster.

Gilbert jotted down his every conversation with this occasionally savant aide, who drives him up the wall – but saves him, too. No trauma is so great that John can’t defuse it with some blockhead theory about frozen prawns or leftfield inquiry into sperm donation. With minimal means, Gilbert brings the character to idiosyncratic life; John has a way of misunderstanding that is entirely his own. With it, he keeps our beleaguered host sane and just-about-smiling as his life collapses around him.

That odd couple narrative glues together Gilbert’s set pieces, several of which hit big in their own right. There’s an eye-opening routine – to demonstrate “Rhod’s Law” that shyness always makes him say the wrong thing – about inappropriate behaviour in a family swimming pool. The carnal comedy of his riff on artificial insemination (“wanking in a hospital”) is hardly unique. But Gilbert – a volcano of shame and dismay – ratchets it to a higher level of intensity than most.

He also flecks it with emotional candour: however high-octane the comedy, it never fudges how scared, sad or emasculated these episodes made Gilbert feel. One story of being bullied into posing for a selfie while grieving for his mum is particularly bleak. Elsewhere, he frequently references his recent BBC documentary on social anxiety, and to a forthcoming one about male fertility. He’s on a crusade, and not just to entertain us. But he does that too, abundantly, in a fine show about the laughter that can be wrenched from fear, despair and one particular seemingly dimwitted driver.

• At Venue Cyrmu, Llandudno, 1 May. Then touring until 13 December.