i work for a homeless shelter and from what I see the following is true.
It can take a long time - 2-3 years with about 2 appeals.
MI is easier. I've have folks with MI get abPproved 6 moths, but people with major organ failure die without approval. I actually had one case where the man had a stoke and was on a ventilator get denied. He died 3 fDays after getting denied the second time.
Using SOAR speeds thing up considerably. Although the process is geared towards case workers the step an documentation can be used by anyone. Here's the link
SOAR Technical Assistance (TA) Center | SAMHSA - Substance Abuse and Mental Health Services Administration
Check out the application tool box for resource