In ‘Schließlich helfen ihm seine Freunde.’=“Finally, his friends are helping him.”, the subject ‘seine Freunde’ comes after the indirect object ‘ihm’ mainly because it's heavier (that is, what linguists call its ‘lexical weight’ is greater): ‘seine Freunde’ is a full noun phrase with four syllables, while ‘ihm’ is just a pronoun with a single syllable. The subject comes before the indirect object If you balance the weights by pronominalizing ‘seine Freunde’: ‘Schließlich helfen sie ihm.’=“Finally, they're helping help him.”. The subject would ordinarily also come before the indirect object if you expand ‘ihm’ into a noun phrase at least as heavy: ‘Schließlich helfen seine Freunde ihrem Vater.’=“Finally, his friends are helping her father.”
A secondary consideration is the distinction between what linguists call topic versus focus, or old versus new information. For example, if after only being helped by strangers (the old information), his friends have finally stepped in (the new information), then you'd say ‘Schließlich helfen ihm seine Freunde.’ or ‘Schließlich helfen ihrem Vater seine Freunde.’ in German; but in English, where there's no case system to free up word order, you'd have to switch to the passive “Finally, he's being helped by his friends.” or “Finally, her father is being helped by his friends.” In contrast, if after helping everyone else, his friends finally turn to help HIM, you'd say ‘Schließlich helfen seine Freunde IHM.’, heavily stressing the last word to make it heavy enough to go after a noun phrase. But if both the subject and indirect object are pronouns, the order is fixed. Even with heavy stress on the last word, *‘Schließlich helfen ihm SIE.’ is unacceptable in German.
If I may give it a shot: 1) Short pronouns like ihm, sie, uns, sich etc tend to go right next to the verb, otherwise they'd feel lost and the sentence just sounds off (same way people don't really say "I told the neighbor of my teacher's daughter it") 2) When the first rule doesn't exclude the possibility, the "new" information that you want to convey with the sentence goes to the end. ("Schließlich helfen dem Mann die Kinder" - finally it is the kids who help the man "Schließlich helfen die Kinder dem Mann" - finally it is the man that the kids help) I hope I got the idea right.
I'm going to assume it has to do with the dative pronoun being used. Man würde sagen: "Schließlich finde ich meine Schlüssel," nicht wahr? Edit: Although, "Eigentlich geht es mir gut," so I guess if there are two pronouns, then nominative beats dative. Off to check some references!