In my experience once you get to the grandparent level, it does start to become more dependent on the discretion of the company. It’s also been my experience that a good employee who hasn’t abused time off is likely to get funeral leave for just about anyone you ask for.
My company has the following policy:
Up to three days of paid leave (provided the employee is already scheduled to work any of those three days) for the death of “a spouse, brother, sister, parent, grandparent, grandchild, parent-in-law, son-in-law, daughter-in-law, brother-in-law, sister-in-law, step-parent, stepchild, step-brother, step-sister, step-grandparent, step-grandchild, aunt, uncle, niece, nephew, or dependent member of household.”
There is also a certain amount of manager discretion – for example, when I had to travel out of state for my grandmother’s funeral, my boss approved an extra day.