that it was United's job to MAKE you happy.

And while I have the deepest sympathies for you and your family over the loss of your grandfather, I don't really see how that is an acceptable reason to change the ticket without any charge. Where does it end? What is a good enough

You should be thankful it wasn't a non-refundable ticket. You would be out the money and not able to change the ticket at all.

While it is sad and unfortunate that you lost your grandfather, the fact that you didn't prioritize this trip you had planned in advance is not United's problem to resolve for you - at least not without an additional charge being involved.