I think this is the 1915 death: [The one above died in 1903].....
1915/3821 Lees David 80Y
Yes that is correct. I found a headstone transcription on Ancestry for this David who would have been born around 1835. His wife is recorded as a native of Co. Galway, Ireland, but unfortunately it doesn't say where David was originally from. With the circumstantial evidence though I am around 95% sure he is the right guy.
There is someone on Ancestry with a family tree for David Lees which does indeed say he is born Co. Tyrone. Not sure where they got that information from. I may try messaging them to ask. I thought of contacting the cemetery though from the website it seems they don't take genealogical queries.
Not sure how it will help here, but this is the obituary of brother Samuel H Lee from Illinois;
