What happens to Tidus after you defeat sin in Final Fantasy X

Tidus was a dream, a person dreamed into existence by the Fayth, along with his father, his home city, etc. The fayth were weary and wanted release from their non-existence. They helped Tidus and his friends defeat Yu Yevon, the power behind Sin. With Yu Yevon defeated, the Fayth could stop dreaming and pass on to the afterlife, but that meant that Tidus ceased to exist, as he was only made real due to their dreams.