www.gov.uk/get-undergraduate-student-loan
This takes your DS through the process (he has to start it off, as it is his loan). Assuming that you are in England and this is his first degree, he will be entitled to the tuition fee loan, which is paid directly to the university, and the basic, non-means-tested porton of the maintenance loan. If he is entitled to borrow more (you can check this on the online calculator), he can indicate in his application that he wants to do this, provide your (plural your, if you live with a partner) contact details and you will be contacted by email to check that you agree to this and to prompt you to set up an account, through which you provide details of your income.
He can start off the process at any time and make any necessary changes later.
Applying 'late' just doesn't guarantee everything in place for the start of the term, but what they tend to do is approve the basic and adjust it upwards later, if relevant.
(If you work out that he will only get the basic maintenance loan anyway, there is no need for him to provide your details, btw).
Re accommodation, the process will be set by the individual university, so he needs to check the relevant web pages.