When word reached him in Boston that his mentor’s home had been hit during an Israeli airstrike in Gaza early Sunday, Dr. Osaid Alser joined an online vigil.

“We could only pray for his survival,” Alser later told The Daily Beast.

He prayed and waited as recovery workers dug through the rubble of the apartment building where Dr. Ayman Abu al-Ouf and his family had chosen to live because it was near the biggest hospital in Gaza, where he served as both head of internal medicine and chief of the COVID-19 ICU.