Hi Hirdy
If you are successul in finding a death entry in the Parish Registers, you are unlikely to be able to confirm parents' details from there unfortunately. Official registration began in Scotland in 1855 and entries in the Old Parish Registers in the main contain very little info, although sometimes you can find the odd entry that includes a little bit more than expected.
From IGI entries which give some of the children for John Belfrage and wife Margaret Storrar (a few spellings for this surname!), this looks to be the family in 1841. Likely mother Margaret had died by this time:
John Belfrage 50, Linen H L W
Henry Belfrage 20
Elisabeth Belfrage 20
Lillias Belfrage 15
Jean Belfrage 14
Isabell Belfrage 12
Janet Belfrage 10
Address: Cash East, Strathmiglo Fife
And for 1851 - spellings on the transcription are not great

:
John Belfruye 64, Hand Loom Weaver Propietor Of 2 Houses b. Falkland
Elizabeth Belfruye 29 b. Falkland
Jean Belfruye 25 b. Strathmiglo
Janet Belfruye 20 b. Strathmiglo
James Belfruye 9, grandson b. Auchtermuchty, Fife
Robert Sinssay 13, daug's son. b. Crommon (Crammond?), Midlothian
Address: Strathmiglo, Fife
And last entry I can see for him:
John Belfridge 74, hand loom weaver b. Falkland
Isabella Fair 29, daughter
David Fair 4
Address: Stewart Lodge, Strathmiglo
Given the date of this census, you should be able to view John Belfrage's death cert on Scotlands People
www.scotlandspeople.gov.uk This would let you confirm his parents' names, if known to the informant of his death.
Have you got access to Ancestry? There are a couple of family trees on there following the line of children Henry and Isabella.
Monica
