So before you can apply for SH you need to meet the eligibility criteria which first and foremost is a ‘local connection’ - meaning you are either living in the area already or you have parents or siblings within that local authority area, or you have a full time contract of employment in said area.
You also need to earn under the threshold set within that area and have savings below a certain amount ( in my area it’s under 32k salary per annum for a single person) London may be more.
You can apply and create an account for SH whereby you will be given a banding depending on need A-D. A being the highest. It’s all about prioritising need -
Roughly
Band A - Yop priority for SH
Care Leavers,
Veterans,
Pregnant women who need to leave their current accommodation
Those already in temporary accommodation, waiting for housing due to eviction, or act of god eg flooding /fire
People escaping DV or families moved due to threat to life ( child exploitation/gangs/ stalking)
Asylum seekers who have been given right to remain
Type 1 diabetic homeless - they need a fridge to store insulin
Child over 1 in a first floor or above, flat
Disabilites that mean current accommodation unsuitable eg stairs /access
Band B
families who are overcrowded- needing an extra bedroom as only two kids can share past 10 if opposite sex, and only two allowed per room of same sex also
Notice and threat of eviction
Band C
Circumstances such as an autistic child needing own room preferably rather than sharing
Anti social behaviour where you currently live
in fairness not much different to a Band D in reality
Band D
You are in housing already with parents or renting or staying with friends and have a home
Unless your son is a care leaver or a veteran, an asylum
seeker in temporary accommodation. with leave to remain, pregnant, about to be evicted or has significant disabilities it is highly unlikely he will get SH especially in London