Hannah,
I have a suggestion which may explain why Michael senior died in Cashel workhouse. In the 1900s there was no state healthcare system in Ireland. In general, if you needed medical treatment, you had to pay for it. However if you were in the workhouse and needed treatment, you got it free. More or less every workhouse had an infirmary attached, and Cashel certainly did.
So you do see people going to the workhouse, not only because they were destitute, but also because they were ill and couldn’t afford to pay for treatment. The official line was supposed to be that the workhouse was a last resort for those with no assets or other means of support, but I have seen a lot of people being admitted to workhouse infirmaries who, from censuses and other sources, would appear to have had some means and family to turn to. So I am not quite sure what was happening there. Perhaps they stated they had no other resources, perhaps when they saw how ill the person was some workhouse masters just took a benigner approach than might have been expected by their general reputation. A clue can sometimes be found in the workhouse admission records. If a person was admitted to the workhouse because they were destitute, you’ll just seem them recorded as admitted. However if they went straight to hospital on initial admission, then it usually says “to infirmary” or words to that effect. So that might be a clue as Michael’s circumstances. Here’s a link to information on where Cashel’s records are kept:
http://www.workhouses.org.uk/Cashel/