People have a tendency to multiply words for various reasons, good, bad or indifferent. Personally I prefer to use less common synonyms even if they might be unfamiliar to some, in situations where it’s critically important to convey a very nuanced meaning and I think my audience is up for it. But I’m the kind of person who does an in-place digital dictionary lookup if I am not familiar with or certain of a word. Not everyone is. Some people positively loathe words and are intimidated by reading. That is why you assume in self-defense that for any given email, most people only read the first and last sentence and assume what is in between the two. So you try to keep emails to 2 sentences 
That’s also within the typical email use-case – someone trying to plow through too many emails and get them out of their inbox or at least marked as “read”.
Now a word like “unalive” strikes me as a waste of effort. It doesn’t convey anything that “dead” doesn’t except, arguably, the fear and loathing. And once a person who hasn’t dealt with the fact of their own mortality, figures out that unalive = dead, they will soon enough attach the fear and loathing to the new word, anyway.
The need to “comfort rather than offend” is an interesting question. I come from midwestern fundamentalist stock, a double whammy in this regard. The operative aphorism is, “if you don’t have something nice to say, don’t say it”. Or put another way, if I find something you say upsetting or challenging or threatening, it means you are bad, and can’t possibly mean anything else, such as, maybe I need to re-evaluate MY assumptions or priorities, or become more empathetic or less thin-skinned or make fewer galloping assumptions about Others, or whatever.
There are certain classes of people it’s functionally impossible NOT to offend, so I don’t put much effort into avoiding offending them. Fundamentalist Christians tend to be very much that way. Their tender sensibilities must be coddled at all times to the point of walking on eggshells – and fuck that, I ain’t doing it anymore. Their issues are their problem, not mine. That doesn’t mean I’ll be gratuitously crass or mean to them, but it does mean that I don’t lay awake nights rehearsing how to communicate with them. I say it like it is, and the chips fall where they may, for the most part.
On the other hand I am a non-threatening, innocuous cishet white guy with no tats or other scary signifiers, who could pass as one of them credibly, in social matters (I used to be one of them after all) … so … I’d have to work a bit at offending them. I admit to not bringing up my metaphysical (un)beliefs unless directly asked, and to not challenging every last thing that comes out of their mouths (it’s too exhausting). Particularly when I’m a guest in their home – it’s their home, so to a large extent, their rules. If they need to compulsively thank Jebus for the food before anyone touches it, I let them do that. Whatevs.
Like everything it’s a balance – in this case, between being real / genuine, clear, and honest, and being kind. Treating others like adults even when they demand to be treated like privileged children, can lead to said “children” throwing a tantrum – that would be their problem. Conversely, turning everything into a zero sum contest where I have to win every argument, would be MY problem.