I can tell you having lost many people in my life, some of them closer than others, this is very easy to say until you're the one doing the dying. Some people accept it better than others. I dont think anyone is actually comfortable with the thought. It's just a gradient of "dealing with it".
I'm not saying death is a good time, just that some people have this conception of it like it is the greatest evil mankind faces or something.
My sister is a hospice nurse so she talks to dying people all the time. She says some people cling desperately to life through horrible agony while others are almost impatient for it to happen despite not being in any significant discomfort. So I'd agree that there's a spectrum of being able to deal and I think I will live my life better if I try to be on the "can deal" end of that.
We fear death because our brain needs to in order to survive effectively, but self is ultimately an illusion, a narrative we construct to weave together memory, present, and projected futures. We know this because self is malleable. We are capable of extending our conception of self into our children, our compatriots, or ideals, and trading "our" life for theirs. Similarly, we can collapse self into just our neural pattern and believe that a computer simulation is still us.
Death is really not quite as big a deal as we think it is, in my opinion.