Acc in participles.

Greek Learning Greek
1

ἔργον εὑρεῖν συγγενῆ

πένητός ἐστιν· οὐδὲ εἷς γὰρ ὁμολογεῖ

αὐτῷ προσήκειν τὸν βοηθείας τινὸς

δεόμενον· αἰτεῖσθαι γὰρ ἅμα τι προσδοκᾷ.
Menander, fr. 4
τὸν δεόμενον is probably instead of Dat. see 2148d, and why the article before δεόμενον?

2

τὸν…δεόμενον is acc subject of προσήκειν

3

oh, αὐτῷ is used instead the reflexive pronoun ἑαυτῷ. And the article is generic.

4

I think you’ve got it. αὐτῷ refers back to the subject of the main clause (“οὐδὲ εἷς”), called indirect reflexion. The full reflexive αὑτῷ (=ἑαυτῷ, note rough breathing) would also be possible grammatically, or οἱ, the semi-reflexive.