What happened to Mendeleev's mother after he was accepted into St. Petersburg University?

"Although he was not accepted, his mother was determined to give her son a first-class education and they walked to St. Petersburg. That same year his mother died and at the age of sixteen, Dmitri was orphaned."

his mother died i think

Explanation:

Although he was not accepted, his mother was determined to give her son a first-class education and they walked to St. Petersburg. Dmitri was accepted into the Institute of Pedagogy on a full scholarship. That same year his mother died and at the age of sixteen, Dmitri was orphaned.