Paalam Mabini Castro | SUN 8/2, 4pm

July 29, 2026, Reminder - Invitation from the Castro Family

Our beloved Mabini has answered the final call today and has taken his seat in the ballpark in heaven, where every game is played under perfect skies.

For as long as we can remember, Mabini and Cris have been faithful members of the Red Sox Nation, celebrating every triumph, enduring every heartbreak, and sharing a love that, like baseball itself, stood the test of time.

We will miss his dry wit.

We will miss the gentle rhythm of his bass.

We will miss the sparkle in his eyes as he lovingly teased Tita Cris—at home, and in the hallways of IP.

We will miss his quiet humility, his unwavering courage, and the grace with which he carried both joy and hardship.

In his final moments, he was not alone. Cris was beside him, singing softly, surrounding him with the same love that had accompanied him throughout his life's journey.

His children and apos, Lee, Shirley, and Nicole; Christian; Paul, Myra and Maya; Christi-Anne and Connie will all miss him.

May the cheers and the song “Sweet Caroline” from Fenway echo all the way to heaven, where we imagine him smiling, at peace, and finally home.

Paalam, Mabini.

Mabini Manza Castro, a Philippine-born medical physicist whose career spanned the transformative decades when radiation oncology evolved from a developing discipline into a highly specialized field of cancer treatment, died recently at the age of 89. Working in hospitals in Boston and Worcester from the 1960s through the 1990s, his work provided safer and precise delivery of radiation therapy to patients during a period of rapid technological innovation. Outside the hospital, he was also the primary bass player for the Iskwelahang Pilipino (IP) Rondalla of Boston for nearly three decades, bringing the same dedication to preserving Filipino musical traditions that he brought to his profession.

Early life and education

Mabini Manza Castro was born in 1936 in the province of Bulacan, in the Philippines, and grew up in a country rebuilding and redefining itself in the wake of WW2. After earning a degree in chemical engineering from the University of the Philippines Diliman, he joined what was then called Shell Oil Company, beginning a career in chemical engineering that would soon take a different turn.

A friend’s teasing suggestion that he might be afraid to sit for a scholarship examination pushed him to take the test that changed his life. Scoring high, he was offered graduate study in the United States and chose to pursue a doctorate in nuclear physics at the Massachusetts Institute of Technology, a decision that set him on the path to medical physics.

Move into medical physics

At M.I.T., Dr. Castro immersed himself in the rapidly evolving world of physics at a moment when its medical applications were just starting to reshape diagnosis and treatment. When his adviser moved to Tufts University, Dr. Castro followed, completing his graduate work and turning toward clinical practice as a medical physicist.

He joined Tufts Medical Center in Boston, where he worked in the physics of radiation and imaging in support of patient care. He later moved to Worcester Memorial Hospital, which became UMass Medical Center, continuing his work there until his retirement in 2006.

Life in Boston and family

In Boston, Dr. Castro met Cristina, who was pursuing graduate studies in education at Boston University. They became part of a close‑knit circle of Filipino students from several area universities who gathered to socialize and to perform folk dances, at one point appearing on local television, drawing on traditions that connected them to home even as they made new lives in the United States.

The couple married and raised their children in Massachusetts, with their family life shaped by both academic schedules and community events. Their household blended science, education and culture, and their children — Lee, Christian, Paul and Christi‑Anne, and their German Shephard “Jana” — grew up surrounded by the rhythms of Filipino music and dance as well as the routines of American schools and hospitals.

A second “career” in music

Although Dr. Castro played guitar casually over the years, his musical life deepened when he joined the IP Rondalla, an ensemble of plucked string instruments rooted in Philippine tradition. The group was founded in 1986, when Cristina invited the conductor and composer Michael Dadap to start a rondalla composed at first of students; Dr. Castro was watching the initial workshop when Mr. Dadap turned and told him they needed a bass player.

Dr. Castro agreed without hesitation, taught himself to read bass clef and took up the bass instrument that underpins the ensemble’s sound. He played with the IP Rondalla for nearly 30 years, becoming a stalwart presence whose steady lines helped carry folk tunes, protest songs and community celebrations across generations of performers. Dr, Castro traveled internationally with the rondalla on tours to the Philippines and Europe, as well as numerous performances around the United States.

Survivors

Dr. Castro is survived by his wife, Cristina Castro. He is also survived by his children Lee Castro (Shirley Atenta), Christian Castro, Paul Castro (Myra Liwanag), and Christi‑Anne Castro (Constance Olson), as well as two grandchildren, Nicole Castro and Amalia Castro.