According to Stephen V. Tracy, the story about the statues was not historical; also he argues that Demetrius later played a big role in the foundation of the Library of Alexandria [REF].
On the accession of Ptolemy Philadelphus, Demetrius fell into disfavour (he apparently supported the wrong candidate, Ptolemy Keraunos), and was sent into exile to Upper Egypt, where he is said to have died of the bite of a snake [REF].