He is Miyoko Tanashi's / Miyo Takano's father.

Tanashi Takemitsu first appears in Matsuribayashi-hen. He has no living relatives left after WWII. Tanashi and his wife died in a bus accident. On his deathbed, he told his daughter Miyoko that there would be no one left who could take care of her, except his mentor, Dr. Takano Hifumi. After this, his condition worsened and he was taken away by some doctors to an operating room, where he later passed away.

(Source: Higurashi No Naku Koro Ni Wiki)