Years ago on E-saṃgha I remember starting a topic about not ever really feeling a great deal of "suffering" in life. Sure I have the regular vexations of egotism and irritability maybe, but nothing very catastrophic that I would even call "suffering" (of course that is not the only definition of duḥkha though).
Some folks responded that I must just be too young, inexperienced, or haven't lost a close relative yet. Both of which could have been possibilities at the time. But now I am older, married, and a business-owner and have traveled the world. And this morning, my grandfather whom has been like a father to me, and whom I've spent a lot of time growing up with, passed away. His heart just stopped. He is the first close relative I have lost.
When my wife got word of his passing she cried a lot, I on the other hand simply "understood" and accepted it. She said I didn't even shed a tear which means I've become cold-hearted or don't love people. I responded that I know all that comes into being must eventually pass away, and that his true nature neither comes nor goes, and in no way differs from my true nature. And so I can "see him" any time. She of course understands impermanence too, although she's not Buddhist, it's an obvious thing. And as a Christian she believes his soul does not perish either, but she is sad that she will never get to see him again in this life.
So simply understanding impermanence won't help at all. You must be detached from materiality. That doesn't however mean I don't love my grandfather and feel for the relatives who are grieving now, especially my grandmother who had him taken off life-support after 50+ years of marriage.
Not suffering doesn't mean I don't care, but the Buddhas have taught transcendental wisdom that is verifiable and applicable in the roughest of life's times. Detachment from materiality does not mean to simply become emotionless and unsympathetic. It must come through the wisdom of emptiness, otherwise hardheartedness will indeed result. Inherent in that wisdom is compassion, sympathy toward those who drown in suffering, not knowing the way out.
Just thought I would share my experience with others.
A few weeks ago, in the midst of losing his mind, my grandfather had the clarity to ask his wife if he is going to die soon.
May he attain a favorable rebirth and quickly attain Buddhahood for the benefit of all beings.
May all those suffering from loss quickly develop prajñā, the wisdom of emptiness, see truth and use it for the liberation of one and all.