Soirry but no good news for you at present.
Because Thomas was baptised into the Catholic faith as an adult means that he was born into the Protestant faith. Protestant records in Ireland are very difficult to get as they have not been generally released for online availability and ar usually only available through the archiving system in Dublin and even then are difficult to access and it is not a free service.
I will contact you again in the next day or two with whatever detail I can find on access and may try to contact them myself to see if I can get any information for you. You may contact me on my personal email address email@example.com of through this message board.
Stay safe & Well,