Hello Isle of Man folk

You helped me a while back, with breaking down one of those brick walls! namely about Martha McGain nee Watterson, [ we had been searching Watson!] We have been trying to surmise why she went to Birkenhead to give birth to her third child Tom , my grandfather [b 1891 just after the census was taken in april] and who was adopted by Job Harding of Birkenhead.
She married William McGain in I think 1883, they had two children William Henry and Annie [who were staying with their Watterson grandparents when the census was taken, Martha was in Birkenhead in a lodging house at this time !]. there does not seem to be any record of William after the childrens birth, although on Tom's birth certificate she names William Mcgain as his father., I have not been able to find a death certificate for William, and am very intrigued as to what happened to him. Can anyone there help please ?