Investigators say last month, Sheaves Slate set the apartment fire in Rogers Park, where Altman fell and died from his injuries.
They say he was a squatter who lit a mattress on fire.
Slate is facing first-degree murder and arson charges.
A public defender was appointed for him Tuesday.
His next hearing is set for June 17.
On Wednesday morning, students at St. Patrick High School ran a drive-thru coffee sale.
One hundred percent of sales will go to Altman's family and the family of slain Chicago police Officer John Bartholomew.