Looked on the LDS IGI site and found 7 births , dates are christening all in Maughold:
James, Jan 27 1822
William, Feb 22, 1824
Catherine, July 5, 1829
Robert, March 11, 1832
John, Apr 26, 1835 , buried Feb 23, 1837
John, April 5, 1840
Margaret, Sept 4, 1842.
James and Mary married March 2, 1822, Maughold , both of that parish, both signed their name so could read & write.
1841 Census, Cardle Veg Cottage , Maughold
James age 55-59
No sign of Robert , no burial on the IOM , "Cathrine's" age is wrong , maybe 11 ?
1851 Census, Ballacriggan, Maughold:
Could not find this 4 on the 1861 IOM Census
There is a burial in Maughold October 8, 1852 of a James Kermeen aged 68.
Could not find a burial for Mary as Kermeen. Found a marriage March 17, 1855 of a Mary Kermeen , a widow , to James Sharp a widower in Maughold.
Found them on the 1861 census in Ramsey, her age is shown as 51.
If you google Amanxnotebook (Thanks to Frances Coakley) and search for Kermeen and Galva , there is a story of your family under " How early Manx Families migrated from Brimfield to Galva" there is also a listing there of
Manx families on the 1880 US census, the family seems to now be under Kerman and Kermine in Ill.
In looking for where Robert may have gone to , I found an article in the Galva Weekly News , Jan 5, 1911 on the death of Mrs Julia Kermeen (Nee Corlett - another classic Manx name) wife of James who she married April 28, 1850. Quotes her children including Robert and John.
On one of the above sites I found that John went to the US in 1855 aged 15, I think on his own.
Margaret may have married William Kinrade in Peoria County January 28, 1860.
If you confirm who you know went to the U.S., will have another go at tracing the missing ones on the IOM