Often an open question: When did our evolutionary ancestors become human? Some scientists actually think that Pan troglodytus (the chimpanzee) should be re-classified into genus homo.
Then again, what's our definition of human? Genetics, usually, but then...
Paloeanthropologists recently found the skeleton of an old...apeman. Probably forty-five years old. Probably needed a cane to walk. Probably lived that way for years. His people were ancestors of European Neanderthals. By speciesist genetic definitions, not human. Heck, they were cannibals. Yet, there is grandfather, clearly being cared for in his old age, perhaps valued for his wisdom. Chimpanzees value the wisdom of elder females who, past childbearing, travel from band to band to trade knowledge. And, of course, modern human females experience the interesting phenomenon of menopause (shared with only one other mammal: The rat). Contrary to popular belief, human females do not experience menopause when they 'run out of eggs' (A human female is born with more egg cells than she could ever possibly produce in a lifetime, presumably redundancy against some of them being damaged or non-viable). Menopause is a programmed cessation of reproduction occurring well before senescence. Why? Likely to prevent those older females, needed for other capacities, from dying in childbirth.
Of course, Grandfather could still reproduce, possibly...male fertility declines with age but not always to zero. Yet, it is a human thing to go out of our way to extend the lifespan of the elderly, even if they are no longer useful. Look at how much money is spent in the west on elder care...sometimes keeping Grandfather alive almost too long.
As for the cannibalism...not so far beneath our civilized veneer. I'd say these people were human.
Now, what definition of human can we apply to beings from another world?