Both tales are great pieces of short horror literature, but they have some similarities that can't be ignored. A Voice in the Night is probably William Hope Hodgson's best horror tale. In both tales you have an older male character plagued with a condition that is virtually identical in both stories. In both you have the spouse of this older gentleman afflicted worse by the condition. Both tales also have a sympathetic visitor (ok 'Voice' had two, but you get the idea...). Both stories have similar endings (the horror comes from the fact that the suffering is not yet over). I suspect that one tale may have 'inspired' the other but both are very good...

Not sure if I would use the term steal... I haven't read Voice but researching it online shows similarities of story - basically along the fungal line. Wiki even lists Fruiting Bodies as a similar work.

 

One is based at sea however, from my quick - non-in depth research while one is strictly land based (if memory serves - it has been awhile since I read 'Fruiting'). It also sounds like Hodgson used fungus throughout his stories, so I am sure that some other fungus related plotlines might read similar as well.

 

To sum up - I think it is pure coincidence, but that is my take. Only so many things a mushroom can do in a story before it sounds like a mushroom from another story... unless that mushroom releases red spores... then that is an entire different story altogether.