Who is Kasim Khan, Imran Khan's son demanding proof of life?

Kasim Khan is younger son of ex-Pakistani PM Imran Khan and British socialite Jemima Goldsmith. Born on 10 April 1999 in England, he is marketing platform MIFU's founder. Kasim has publicly demanded 'proof of life', claiming Imran Khan has been held in solitary confinement for six weeks with no family contact, no phone calls or visits, and complete information blackout.