I must admit I find your posts somewhat difficult to follow - however it would appear from the IoMFHS transcription of the burial reg for New Braddan (almost next door to Ballamona) quoted by Donna that he was buried in a certain grave but that General Registry have no record of his death. I recall that you said the 1901 census showed that he was an inmate of the asylum - presumeably there is an admissions' register giving the date of his entry (& probably his address?), there is I believe a record book of the graves at Braddan New which should confirm the name. It is possible that General Registry have him index under some mistranscribed name.

However the claim he ran a mine 'Douglas Head Fidlers Green' seems very strange - I was not aware of any successful mining activity (other than for silver out of tourists' pockets) that occured on Douglas Head - can you quote your source for this claim. - there is an entry in Lamplugh -
Douglas Head Mine.

Some utterly profitless mining work was done on Douglas Head (Sh. 13) between 1865 and 1871, consisting of a long adit driven in from the cliff at the southern side of the headland, and a shaft on the summit S.W. of Fort Anne Hotel. . The character of the operations will be understood from the following extracts from Sir W. W. Smyth’s reports :—In 1865 the report. states that " a shaft had been sunk for 14 fathoms, and a couple of fathoms driven on a lode coursing N.E. and S.W. with ‘umbery’ gossan, but no appearance of ore; while a cross-cut adit was driving from ‘Billy Gilbert’s harbour,’ which will have to be pushed from 60 to 70 fathoms in order to meet an expected lode." In 1866, the level driving in from the sea had "no appearance whatever of a promising character"; in 1868, it had a length of 80 fathoms in hard ground [Lonnan Flags] costing £13 to £16 per fathom, "the vein a mere string without a speck of mineral in it the whole way"; and in 1870, the shaft had been sunk "24 fathoms on a course termed a lode but having a very problematical appearance and not a grain of any kind of ore."