“But he who comes against him will do as he pleases.” This is to be understood as, “But he [Antiochus III the Great] who comes against him [Ptolemy V Epiphanes] will do as he [Antiochus III] pleases.
“and he will stand in the glorious land.” The “glorious land” is Israel. The Seleucids had controlled Israel for a brief time before this, but now Antiochus III had undisputed control of Phoenicia and Israel, and this control would last. This set the stage for the control of Israel by the son of Antiochus III the Great, Antiochus IV Epiphanes, who was the infamous person who did so much harm to the Jews and who was the clearest type of the Antichrist in the Bible, and who is the subject of Daniel 8:9-14.
“and in his hand will be destruction.” This is idiomatic for Antiochus having the power of destruction. Israel was under his firm control.