Hi Agnes,
Tracing family history can be a little bit tricky the further back you go!
Our friends at Irish Family History mentioned that you have your Great grandad ×3 death certificate which is a wonderful help as a paper trail is extremely useful.
Before 1864 records were kept in the form of church and parish records; while some of these have regrettably been lost over the years, all the surviving records have been sorted into county-based
genealogical centres.
We have a wonderful resource post by Brian Mitchell,
A 3-step guide, that you may find useful. There is a lot of information and useful links within the post.
As you mentioned to our friends at Irish Family History already that he died in Scotland, what other information have you found out about his leaving from Ireland?
Hopefully, our other members will be able to offer some assistance,
Speak soon