Try witnessing both your parents drown as they set sail from Alola.
Try spending an entire youth feeding off the scraps and leftovers of others.
Unloved, unwanted. A terrible waste of life.
Can you? No? That's just fine.
So Cubone misses his mother. Big woop. Is it not obvious he will never be prepared for the real world should he continue to believe in this paradisaical fantasy?