The Alameda County Sheriff's Office said the attack happened around 8 p.m. in the 16200 block of East 14th Street.
Rafael Betancourt was charged with suspicion of attempted murder and mayhem.
Authorities said the suspect caused severe damage to the elderly victim's face and skull, including a brain hemorrhage. He is in serious condition.
The suspect was identified as Rafael Betancourt and charged with suspicion of attempted murder and mayhem.