Just so you don't go away with errant information, Williams did not commit suicide. He choked on a bottle cap. Theories differ on how it happened, but suicide is not one of the possibilities usually considered.
In A Streetcar Named Desire, Tennessee Williams is identified in two characters: Blanche Dubois and her husband, Allan Grey.
In Blanche we see the debauched Williams, addicted to pills and alcohol, slowly descending into depression and self-destruction, and trying her best to come back to the surface to no avail.
In Allan Grey, we see Williams also in that they are both homosexual and seem to have a problem with leading double lives and accepting their identities until their deaths.
The link includes more information on Tennessee's biographical facts to help you see more similarities.