I don't know why my mind is mulling over this, but... here goes:
Suicide, assisted suicide, and abortion could all be considered self-centered acts; because "the killer" is deciding when to end a life, usually to prevent prolonged periods of pain for "the victim"...
Instead of allowing nature to run it's course, we are (usually) denying "the victim's" associates an opportunity to be near in the declining time of "the victim's" life. Said another way, "the killer" is going forward with decisions that ultimately put them at ease (if they succeed) at the expense of others' grief cycles.
---------------
However, there is the "prolonging life artificially" argument - at what point can we decide to turn off any assistive technology (like respirators or feeding tubes or...) and allow nature to run its course? Also, are there any medical conditions severe enough, in the present and future pain and discomfort that they cause their subjects, to justify an end of life scenario?
Here, the self-centered nature changes, where the associates are acting self-centered, in a fashion, by placing their joy and happiness at keeping a "victim" alive, and yet the victim is dealing with much discomfort.
------------------
This is one reason I like the idea of living wills, even though I still need to get one. I, personally, would prefer to be kept off of life support, if the situation were to arise, partly because I don't want the high medical costs it incurs and partly because I don't want to prolong suffering, if I can avoid it.
------------------
Note: I realize that suicide is not the same as assisted suicide, and they are not the same as abortion.... but I do think they share some common arguments?
Hopefully, now, I can get some sleep...