it's fascinating to me that every member of the party pre- and during loops treats siffrin with some flavour of alienation. like, bear with me. this post is going to sound like im here to give a hot take that the party are Bad Friends, Actually, but i promise you that's not what i mean. you're with me? okay. let's go.
isa idolises him (in the having a crush on someone type of way).
mira views them almost as a book character (the whole "the aura! the mystique!" conversation).
odile calls them a child to their face multiple times.
bonnie is... well, bonnie. kid is coping how they manage.
in the very beginning of the journey we have isa and mira, who, out of all five, are the most familiar to eachother. they're from the same country, they both actively follow the change religion, they both occupy (or occupied, in isa's case) well-respected positions in society, they're very close in age and i would assume socioeconomic statuses. they share a lot personality wise, too. they're both anxious about not being enough, about not changing enough, they're both open and emotional and affectionate, they even both like romance novels! they are very in eachother's comfort zones. they are very understandable to eachother.
then there's odile. she is as different as it gets – she's ka buan (and well half vaugardian but nobody knows that), she's old, she has different religios beliefs and different history with body craft, she's confident, self-secure, reserved, sarcastic and at times cold and makes it very apparent that she's not into openly displayed affection. but also, she is actively choosing to be seen this way. she is comfortable with being perceived like this.
and then, there's siffrin. a mysterious traveler with mysterious past that doesn't like to be touched and never talks about his feelings. where are they from? what he believes? what did he do prior? why did they join them? noone knows. situation kinda similar to odile's, but kicker is, we know siffrin does not want to be seen this way.
mira, being a somewhat sheltered not very experienced young adult (she's from dormont with population less than a regular highschool class, and has been living in the house for some past years) with more familiarity with books than with real world obviously views them more as a cool character than a person. and i can't blame her! siffrin doesn't help her view them any differently either.
isa i assume catches feeling almost immideately (the whole journey takes less than a year, sif is second to last to join and we know that isa's crush has been going for months) and it's universally hard to not idolise and idealise the person you're having a crush on, so even tho isa is more experienced than mira, i imagine he fails to see siffrin as a whole person too.
odile out of all of them grinds my own personal gears the most. i love you, old wise lady, but oh god. the amount of times she refers to the party and in particular siffrin as kids or children is sure something. and the thing with kids is that you generally don't view them as equals, so, no "seeing siffrin as a person that he is" there either.
that's general dynamics. now to what interactions we actually see in game:
odile mocks siffrin for being forgetful. every time siffrin forgets a word, everyone reacts as if they don't remember that vaugardian isn't siffrin's native language. both isa and mira behave patronisingly towards them (jokingly, but still). the whole party spends some time comparing siffrin to a wild animal in the dictionary conversation, mira saying "what a perfect analogy" with stars in her eyes. one time siffrin desides to open up and tell them about stars, they mock him. when he kills that sadness more violently than usual, they all look at him as if he murdered a baby (i still don't really get why btw. they've been fighting side to side for months). the whole ghost event. ohhh ghost event my beloved.
all of these, for me, point to a very deep yet unacknowledged disconnect between siffrin and the rest of the party. the not-understanding. the unfamiliarity. the alienation. siffrin is other even in their own little ragtag bunch of misfits.
now AM I SAYING that means that the party is bad actually?? no!!! for every interaction i named there's multiple others with them being supportive and warm to sif. also, siffrin, famously, is very bad at telling when something bothers them, so noone whould even know if they were doing anything that upset him. and, on top of everything else, i think it's very natural for a party of very different people traveling in a lot of hurry and discomfort and plain mortal danger for months to develop a bond where "i would die for you, my siblings in arms, but i also will poke fun at your religion when it starts to sound too impossible for my worldview. what do you mean stars are there in the daytime too? don't be silly". i actually really appreciate their friendships being imperfect, because it's so much more interesting and thought provoking this way. like, I've been thinking about this for weeks.
and also, this specific type of imperfection plays into the core themes of siffrin's character. to be welcomed, adored, loved, even, but not understood. not recognised. not known. and to not even try to explain untill the world is literally ending.