To answer this we need to establish very clearly what has made these individuals "unsuccessful" and causes such individuals to wander around at night, "bat-like" as the text describes them. Let us remind ourselves of the second paragraph, which gives us an excellent analysis of why these people, Gortsby thinks, walk around at dusk:
Dusk, to his mind, was the hour of the defeated. Men and women, who had fought and lost, who hid their fallen fortunes and dead hopes as far as possible from the scrutiny of the curious, came forth in this hour of gloaming, when their shabby clothes and bowed shoulders and unhappy eyes might pass unnoticed, or, at any rate, unrecognised.
Thus we are told the unsuccessful people have "fought and lost" in the game of life and have either suffered "fallen fortunes" or "dead hopes." The reason why they walk around at dusk is because it gives them the anonymity they desire and crave, so that they can walk around without being identified and having their failures established by others.
How can we help such individuals? Well, I would suggest that such people need some kind of support group where they can discuss their "failures" and "fallen fortunes" so that they can begin to come to terms with them. Then, perhaps they need help and advice to see that "failure" is in fact not the negative experience that we so often think it is, and that to fail at something is actually incredibly positive. This should help them reflect on what they have learnt and give them back their self-confidence.