Some members said they were haunted by his final Facebook post: "Flu 2x sucks... feel like death."
Giszack graduated in the FLHS class of 1976 and was remembered as a dedicated son to his ailing mother, Elizabeth Giszack -- longtime supervisor of the Memorial Pool.
Condolences continued Monday.
"Mike was vigilant regarding his mom and I am stunned by this news," one of Giszack's former peers wrote on Facebook.
"Shocked beyond words," another said.
Vander Plaat Caggiano Funeral Home was handling arrangements.
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