Muhammad Morrar is being treated at Eden Medical Center in Castro Valley. Even if he survives his wounds, he will never be the same, Nelson said.
The beating happened at about 3:30 p.m. Friday at the Sports Plus 1 store at 19367 Mission Blvd.
Nelson said Morrar was likely beaten with a baseball bat.
Aaron Tomlin, 35, of Hayward, was arrested in Hayward on Saturday on suspicion of attempted murder and is being held at the Santa Rita Jail in Dublin, Nelson said.
The second suspect, 28-year-old Christopher Echols, made phone contact with deputies over the weekend and said he would turn himself in but hasn't yet done so, Nelson said.
Echols has addresses in Menlo Park and East Palo Alto and has ties to Redwood City and San Francisco, according to Nelson.
Nelson didn't disclose a motive for the attack on Morrar.
Nelson also doesn't have information on Morrar's age or city of residence because investigators haven't been able to talk to him.