αὐτῷ

From LSJ

κρεῖττον εἶναι φιλοσόφως ἀποθανεῖν ἢ ἀφιλοσόφως ζῆν → that it is better to die in manner befitting a philosopher than to live unphilosophically

Source

French (Bailly abrégé)

dat. de αὐτός.

Russian (Dvoretsky)

αὐτῷ: dat. к αὐτός.