Incredibly sad news. A terrible loss for the left and all the movements he helped to build. And a huge personal loss for Mary. 

John was a fantastic, kind and generous comrade. When I joined, John Molyneux was active in the British SWP, a big name speaker at the annual Marxism event in London. It was surreal years later to have this figure sitting at branch meetings in a community centre in Rathfarnham, but John shared his knowledge & ideas with as much enthusiasm at those tiny meetings as he did at the big ones. His commitment to the struggle for socialism was undying. 

La lucha continua, as John would want. Informed in no small part by his writings and inspired by his boundless energy and activism. Rest in power John. You made a difference.