That was very interesting, I appreciated his opinion, thanks. While there's certainly a lot of reasons why someone would fall into unhealthy life patterns that often lead to homelessness, homelessness itself is strongly tied to the cost of rent. As for drug use, many homeless people start using drugs after they become homeless.

For [homeless] who did use drugs in the last six months, 40% of people started using — more than 3 times a week —after becoming homeless. ...
research finds that individuals frequently use methamphetamine to help them stay awake at night to protect themselves and their property from assault and theft.
https://www.latimes.com/opinion/story/2023-10-04/homelessness-drugs-addiction-encampments-substance-abuse-unhoused-police

It seems the stress of homelessness has a way of causing mental problems and drug addiction even in those who started out healthy.