Anthony Flick is in "very serious but stable condition," D.A. Risa Vetri Ferman said during a news conference on Tuesday.
"I cannot emphasize enough how serious his condition is," Ferman said.
Flick is with other family members.
"My uncle did get a phone call from my aunt and he is awake and he's just talking just a little bit. But so far he seems to be doing okay. [He] doesn't know [anything happened.]," relative Patricia Flick Conrad said.
Investigators believe Flick and his family were the first targets of the alleged killer, Bradley Stone.
The bodies of Flick's parents - Aaron and Patricia - along with his sister, 14-year-old Nina, were found at dead inside a home in Souderton, Pa. on Monday.
Police believe they were shot around 3:30 a.m.
Other victims include Stone's ex-wife along with her mother and grandmother.
Mental health workers are walking neighborhoods in Souderton, Harleysville, and Lansdale, offering counseling services to neighbors who may have been affected by the multiple murders.
"It's really normal to have a really anxious response, to feel uncomfortable where they live. It's a scary thing, so just offering people support," Jessica Fenchel of Mobile Crisis said.
Neighbors of the Flick family in Souderton have been traumatized by the multiple deaths and the ensuing manhunt as police tried to locate Bradley Stone, the suspect believed responsible for the killing spree targeting his ex-wife and her family.
Some are not surprised it all ended with him apparently taking his own life.
"It's not an uncommon outcome for that kind of thing but I'm just glad it's over. Just sorry the whole thing happened," Frank Bucher of Souderton, Pa. said.
"I'm happy. I feel safer now. My kids are okay to come home. It's just great our community can start to get back to normal, but it's going to take a while," Nikki Massey of Souderton, Pa. said.