I think you're essentially doing the right thing of making sure he's aware he has a support system available - but as above he seems to be trying to sort things out for himself, and so I think just making him aware that if there's some major financial emergency he can come to you is sufficient.
In terms of the deposit realistically while renting keeping any part of the deposit should be seen as a windfall rather than a guarantee. Particularly in shared accommodation where the deposit may also cover shared areas where there could be damage not caused by him, there's really no guarantee of getting all or any of it back. That said there are mechanisms to challenge unreasonable deductions to the deposit.
Otherwise if he's actively looking for work, you can try and help by offering to e.g. review CVs, practice interviews or similar with him if needed. I'd avoid sending job listings unless he's asked you to keep an eye out though (as that might feel like you're pressuring him to get a job), and focus on the other stuff you can do for when/if he is looking.