Does " Holmes' sister" refer to " Holmes' younger sister"?

[NewHopeR]

If not specifically pointed out, "sister" in a context usually refers to "younger sister", rather than "elder sister"?

Context:

Porsche Parkman and her husband, William, 19, remember a friendly family who kept to themselves but were supportive one another.
Porsche Parkman became friends with Holmes' sister during their freshman year at Westview, about 3 miles from where the Holmes family lived.

More:
Two portraits of theater shooting suspect James Holmes emerge

[5jj]

If not specifically pointed out, "sister" in a context usually refers to "younger sister", rather than "elder sister"?

No

[NewHopeR]

No

Well, when 'sister' is mentioned, how can we know that she's younger or elder than her brother?

[5jj]

Well, when 'sister' is mentioned, how can we know that she's younger or e older than her brother?

We can't, unless we are told, usually by the use of the words 'elder/older' or 'younger'.

ps. we use only older predicatively.

[tzfujimino]

Hello.
It is mentioned in the article:
"He was really talented, really smart," said Porsche Parkman, 19, who attended Westview High School with Holmes' younger sister,..."

Just in case.

[keannu]

You have the same problem as the Koreans and the Japanese do. I know why you are trying to know it. For in many Asian countries, they never call their brothers and sisters by their name directly and by "brother" or "sister" alone indirectly. In Chinese, they use gege(older brother as "hyung" in Korean or "anisan" in Japanese) or didi/jiejie/meimei(the Koreans and the Japanese do have each separate term for these).
You, I and the Japanese are used to using these specific terms, so when we encounter "brother" or "sister", we always wonder which specific brother or sister it is. But don't care about it. That's the starting point of understanding cultural difference, leading to truly understanding a foreign language.
The cultural difference is that English speakers have equality concept for their siblings, while some Asians have hierarchical one. So when you encounter those terms, it would be better to interprete them as "xiongdi(brothers)" or "jiemei(sisters), which I also love to use and no one will blame it.