Mitgefil
מיטגעפֿיל, mitgefil. Also 'rachmones' or 'rachmunes'.
"Gripe" in Yiddish means "complaint" or "criticism." It is often used to express dissatisfaction or frustration with a situation.
Concerned Sympathy
In Yiddish, you can say "oy vey" to express astonishment or disbelief, which is similar to saying "wow" in English.
You can say "Ikh lib mayn kleyne shvester" in Yiddish to express "I love my little sister."
"Yada" in Yiddish means "to know" or "to know something for sure." It is often used colloquially to express understanding or agreement.
In Yiddish, you can sign a note with love by writing "mit libe" (מיט ליבע), which translates to "with love." This is a common way to express affection in written communication among Yiddish speakers.
You can offer your condolences with a card.
If you want to prepare some notes to express your sympathy for your brother's loss you can use a website called Shutterfly. It will give you a lot of example and I'm sure you will find one you like.
Sympathy can be both a noun and a verb. As a noun, it refers to feelings of pity and sorrow for someone's misfortune. As a verb, it means to feel or express sympathy or understanding for someone else's situation.
It means "Dear God!" in english, and i think it means the same in Yiddish.
It can vary by region but one way is "Ich bin mid" which is close to the German "Ich bin müde."