I'm in close touch with Michael's second family but they are as much in the dark as I am.
There doesn't appear to have been any contact following separation and the children stayed with their mother although 'R', the eldest of Michael's and Eileen's children, apparently attended Michael's funeral held in Limerick in 1975.
Good idea to check obituaries; I didn't stop to think that his Ballina family might have posted something so I'll follow that path and see where it gets me.