looking at a record 1823-1833 The Tithe Applotment Books
http://titheapplotmentbooks.nationalarchives.ie/reels/tab//004625680/004625680_00541.pdf it shows two single line entries for the whole county
Fowley Owen Kilcare townland Kilmacteige parish Sligo 1825
Fowley Owen Kilcare townland Kilmactranny parish Sligo 1833
this could be the same person 8 years later or two different people the same website allows you to search for last name spelling variations
moving to Griffiths Valuation which you know well using
https://www.failteromhat.com/post1845.php produces
Fowley Hugh Sligo Church Lane St. Johns Sligo
Fowley Jacob Gortnagrelly Drumcliff Sligo
Fowley Hugh Gortnagrelly Drumcliff Sligo
Fowley Daniel Gortnagrelly Drumcliff Sligo
Fowley Patrick Glackbaun Cairy Sligo
i agree it looks like jacob is the father
for more information including a boundary map if you are lucky go to
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=doNameSearch&Submit.x=37&Submit.y=9&Submit=Submit&familyname=Fowley&firstname=First+Name&countyname=SLIGO look up the details for each of the three living in same townland then move to maps find the townland and find the outline of boundaries and buildings.
Daniel has map ref 2a in Gortnagrelly townland. looking that up shows 14 acres and house valued for tax at ten shillings pa next I look up modern google map and satellite and often spot streetlevel scenes of the current buildings sometimes including bits of the older bldgs
3 males living in same townland could easily be close relatives or father of Daniel . I would next search townland mapsand print them out to discover how close all the fowey are together.
Gortnagrelly lastly Griffiths valuation was followed by valuation continuation books held in Dublin
have fun