PAL Holdings’ President Lucio “Bong” Tan Jr., son of Philippine billionaire Lucio Tan, died Monday after collapsing while playing in a basketball game days earlier. He was 53.

The younger Tan succumbed to brain herniation, the Philippine Star reported. He had entered a hospital on Saturday. PAL Holdings, the listed parent of Philippine Airlines, didn’t immediately respond to a request for comment.

“His untimely passing leaves a deep void in our hearts and our group’s management team, which would be very hard to fill,” his sister Vivienne Tan said in a statement, referring to him as “an elder brother whom we all relied on for advice, counsel and leadership.” He’s survived by his wife and two sons.

The sudden death of Tan Jr. casts doubt over the leadership of the airline, especially as he was seen as a potential successor to his father, said Rens Cruz, an analyst at Regina Capital Development Corp. His passing “will definitely add a layer of uncertainty,” Cruz said.

Tan Jr. had taken over as president and chief operating officer at PAL Holdings on October 28. He was also the president of Tanduay Distillers and Eton Properties Philippines, and a director of LT Group and Philippine National Bank.

Shares of LT Group, the holding company of the 85-year-old patriarch, fell as much as 1.8 percent, while PAL Holdings rose 6.8 percent in Manila trading Monday.

Meanwhile, John Gokongwei Jr, a Philippine billionaire who built a business empire spanning from banking, retail to aviation, died late Saturday evening. He was 93.

One of the tycoon’s most recent successes was the steady ascent of Cebu Air, a carrier he founded in 1996 with only four aircraft. It endured a difficult start with a plane crash that killed 104 people and struggled against flag carrier Philippine Airlines.

Its low-cost model allowed it to tap burgeoning travel demand in the country and the region. Not only did it eventually surpass its rival to become the country’s largest domestic carrier, its passenger count is poised to increase tenfold by this year to a record 23 million.

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Photo Credit: Philippine Airlines Airbus A320-214. Lasta29, Flickr