For some nine years, the most difficult decisions I had to make did not concern my personal life or job, but the Catholic high school that I served as a volunteer trustee. This week, the school announced it will close in June. I'm in mourning.I'm not privy to the decison-making involved; I've been off the board for several years. But the reason Brooklyn's Nazareth Regional High School will close is obvious: total enrollment for the four years has dropped to 311 - nearly the same size as my 1971 graduating class. As recently as 2006, the school had nearly double the current enrollment, 602. Since tuition makes up the bulk of revenue, it would be very hard to absorb such a loss (especially since there were already substantial debts).It was a wonderful new school in my day, run by the Xaverian Brothers with a staff made up largely of talented, innovative young teachers, many of whom would go on to distinguished careers elsewhere as they got older. The combination of youthful enthusiasm and post-Vatican II optimism made it quite a place. The tuition, subsidized by the Diocese of Brooklyn, was $200 a year.By the late 1970s, the Diocese of Brooklyn - first to feel the pinch of hard times because it is the only entirely urban diocese in the country - cut the school loose. A lay board was formed to run it, anticipating a model being adapted now in many Catholic schools. Changing with the demographics, the student population shifted from nearly all-white to entirely minority, with a large number of Caribbean-American students. The all-boys school accepted girls.The school was slow at first to connect with the Caribbean community, but eventually did so. When I became involved in 2001, I saw that the warmth between teachers and students that I experienced had continued. This, I believe, is what makes Catholic education special - the commitment to the whole person. This is why the school graduated and sent virtually every student to college. And the quality of the school - the continued dedication of the staff - is why I thought it worth some effort, and a lot of difficult decisions, to try to keep the school going.Much of the news coverage now is focusing on Nazareth's unlikely rise in the past two or three years as a nationally ranked girls' basketball power. But that misses the point of what made Nazareth stand out.Like other Catholic schools, Nazareth offers a rounded education ("wisdom, age and grace" was the motto when I was a student) that parents would want for their children. But the sacrifice being asked was just too much for many: Tuition and fees now list at $7,785. This is six times the amount my parents paid in 1967, adjusted for inflation.Costs rose, no doubt, because there were fewer Xaverian Brothers on the faculty (although the brothers helped the school in other ways). But if Catholics donated like Mormons, Nazareth and plenty of other now-closed and struggling schools would be flourishing.Some alumni were very generous, but the overall percentage of those who gave was very low. Foundations shied away, and the biggest have put their money on charter schools, which have not proven to be a solution. The result: ever-rising tuition paid almost all the costs. I hated to vote for those tuition increases, but there was no other option.One of the laments often heard when a Catholic school closes is that nobody knew the situation was so dire: "If only they had asked for help." Realize, though, that the school administrators are in a difficult spot. If they state what should be obvious - "If we don't get more donations, we'll have to close" - parents will be reluctant to send their children there for fear the school will close. Donors - foundations, in particular - will be reluctant to give money to a school that might close.For my part, while I am sad for the students, faculty, staff and board, I'm happy that Nazareth was able to accomplish much good in its 50 years. Given the circumstances, the school did well to make it through the past 20 years. Working in the newspaper business has taught me not to expect permanence; just do your best to serve the public while you have the chance.But if you value urban Catholic schools, don't wait to hear an S.O.S. before donating. By then, it will be too late.Photo: Students at a walk-a-thon fundraiser; www.nazarethrhs.org.