Is Hikari supposed to be a mother figure to Asuka?

[Grimmjow]

Hikari is Asuka's only real female friend. She cannot relate to Misato who is much older and experienced than she is. She cannot relate with the emotionally distant Rei who she sees as competition on multiple levels.

On the other hand, Hikari does not come with any emotional baggage, thus making it easier for Asuka to talk to. In addition, Hikari does not force issues or conversations. She simply stays with Asuka and offers support.

[gwern]

There's so little material on Hikari that she's hard to discuss. The Platinum commentary mentions her twice, I think, once in a list of names, and once as 'class representative'.

Newtype 1996 gives us some actual discussion of Hikari:

However, Touji was selected as the fourth candidate, and when EVA device #1 attacked Touji’s EVA device #3, this relationship was broken. Kensuke’s dream of being an EVA pilot was also broken, and Hikari’s feelings for Touji too…

The ‘promise’ of a personal relationship was seldom made in “Evangelion” and it made a touching picture that Hikari, an honor student and class president, was charmed by Touji, who had a bit of an image as a delinquent. Hikari was portrayed as a girl who was wishing, “I’m not yet able to confess my feelings, but I want to transmit them somehow,” and Touji, either knowing or not knowing about her feelings, promised to eat the leftovers of her box lunch. Touji, Hikari, and Kensuke; from here on we will not be able to take our eyes off of them.

I especially find interesting the insinuation that Hikari's crush on Touji is crushed by Eva-01's crushing of the plug. (If you'll pardon me.) Not exactly the usual 'love conquers all', but a somewhat more cynical take: high school relationships are just practice and not 'real' love that could survive a problem like maiming.

Looking through the script, I'm not sure we have any positive evidence for Hikari dropping Touji (out of pity & disgust?); we just have one offhand line that 'Suzuhara is still in the hospital',

There's another description of Hikari in the theatrical pamphlets:

She [Horaki Hikari] has a very down-to-earth character, and takes her responsibilities as Class President seriously. For this reason she is somewhat shunned by the boys in the class. While outwardly appalled at Touji’s unmannerly character, she secretly harbors affection toward him, but never says so openly. She is one of Asuka’s few friends in Japan.

(One wonders if the remainder of the friends are Misato & Shinji.)

This doesn't help much either. We already knew she was some sort of friend, but it doesn't say anything about any sort of sister or mother-like relationship. There's just not enough there to say.

[Speedy_pig123]

Personally I think she’s just more of a friend shes pretty close to, we don’t see much of Hikari aside from a couple of episodes. A notion that I disagree with though is concerning Hikaris response to Asuka while she’s staying over. I do truly think that Hikari really does care for Asuka and she really does want to help her, that being said imo Hikari just can’t and is just mentally exhausted at this point. We rarely see the standpoints of civilians during all this but from what we can kinda gather and assume, Hikari is doing a shit ton of stuff and shes also dealing with her own problems as well. We can assume Hikaris mom is dead and we don’t know about Hikaris Dad or anything so we can assume that she’s effectively the Mother to her younger and older sister. She has to take care of them and cook and stuff cause her older Sister is probably too busy with studying and her younger sister is probably too young. On top of that we can assume shes a good student so shes definitely having to study a lot herself. From what I’ve kinds noticed atleast from what I remember, shes not exactly “popular” only really being in an elevated position due to being the Class-Representative so as far as we’re concerned she could probably be pretty lonely. Then the Angels attack, effectively the last 13-14 years she has been working through is made even harder for her cause now theres weird ass monster aliens attacking her City full force, her class gets slowly smaller and smaller so whatever friends she mightve had before the attacks have probably left the city and throughout the series we still see it get smaller and smaller. We know Hikari has a crush on Toji which she seems not to sure how to really express but she does try and then Toji gets squashed and loses a leg and is forced to sit in a hospital so now her crush is hurt. On top of this the class that shes in is definitely without a doubt not the same again, Tojis energy is gone, Shinji iirc decides to just cut school entirely, and Kensuke to me atleast is pretty chill so he wouldn’t really do much. Then Asuka gets mindraped and decides to hang out at Hikari’s house where she just kinda shuts everything out and doesn’t really say anything. At this point Hikaris life is completely upside down, her school life is somber and humorless, her crush is badly injured, her friends are pretty much gone, Asuka got mindraped, and shes effectively a teen mom who is a good student. I think Hikari as much as she wanted to help just couldn’t emotionally handle it and gave that kinda half hearted response

[Blockio]

Yeah, Hikari is failry definitively not a mother figure; just a normal, platonic friend. Only one Asuka has, so towards the end she does slip into something of a role of being a familial anchor point

[Asunji_Yuko]

Hikari's a trusted, real friend more than anything else.

I wouldn't go that far. Their relationship seems somewhat distant. When Hikari tells Asuka that she did her best, she doesn't know how crushing that statement is.

If you consider Asuka telling her mother she "wouldn't be lonely anymore" when she learned she'd be an Eva pilot, it seems like she didn't really have any friends growing up. Not surprising, few college kids are gonna relate to a 10-13 year old girl.

And considering Hikari's personality as the class rep, what with always wanting to be fair and pretty much nice to everyone, she chose to befriend Asuka so she wasn't friendless.

tl;dr Hikari was friends with Asuka because she's super nice and Asuka never had any real friends before