Assuming the usual attribution for John Quilliam is correct then the family at Ballakelly Marown is
John Quilliam = Christian Clucas Ballakilly Marown
John 29 SEP 1771 - Lt Quilliam according to Train (not exactly the most reliable source) impressed off a collier in Castletown Harbour
Elizabeth 13 MAR 1774
Thomas 28 APR 1776
William 11 OCT 1778
Margaret 12 JAN 1781
Mary 23 FEB 1783
Robert 27 SEP 1789

so if a brother, then Robert had a child at age 20 which is somewhat young assuming my identification of Samuel as son of Robert + Ann Winn is correct -

(The only Winn/Wynne I can find with manx connections is Jane Crebbin (da of Rev Crebbin) who married Edward Wynne at Santon 11 OCT 1785 Santon - I think she is buried 1811 at Santon, it is also possible that Edward was the Lieut Wynne thanked in 1812 Quayle's Agriculture - however no children found & I think Edward remarried in 1812.