I don't doubt that he's a decent person; just...odd. He's living in CCL if he believes his leadership would increase the Labour movement's membership. And I'm suspicious that he was involved with Militant Tendency. He certainly knew and sympathised with many MT members, and for that alone he should be excommunicated.
But no; the current MPs won't support him, but the oddly bizarre voting system the Parliamentary party use to choose a leader could see him squeeze through. If he does, it will be the end of the LP as we know it, and a gift to the Tories, and yet he can't see that. Which in itself makes him unsuitable.
And I don't know how he has time to be an MP, let alone Leader, since he's Chair of the All Party Parliamentary Group (APPG) on the Chagos Islands, Chair of the APPG on Mexico, Vice-Chair of the APPG on Latin America and Vice-Chair of the APPG on Human Rights. He is also a Member of the Bolivia, Britain-Palestine, Great Lakes, Cheese, Dalits, Cycling, International Parliamentary Union and Traveller Law Reform APPGs.