Virginia-American The only source for this allegation was an evangelist who called herself "Lady Hope"
They often expurgate Darwin's religious views when publishing his Autobiography, but he did talk about these. T. A. Goudge remarks that Darwin had difficulty with Christianity, but that he did not write as an atheist.
In the final chapter of the Origin of Species he speaks of laws having been "impressed on matter by the Creator" and of life's powers "having been breathed by the Creator into a few forms or into one."
In his linear view of things it appears that Darwin could not see the benevolence of a first cause, yet Darwin also spoke of his seeing how this "wonderful universe, with our conscious selves, arose through chance." As a result, so it seems, he preferred to remain agnostic: "the whole subject is beyond the scope of man's intellect. . . . The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain Agnostic." [cited by T.A. Goudge in the Encyclopedia of Philosophy]
I understand he was an agnostic and/or Deist.
The phrase "just before his death." tells us that Fabian was referring to the Lady Hope deathbed conversion yarn.