The incident took place in East Delhi's Geeta Colony area where the victim, identified as Lokesh, lived with his family.
Police said they could not ascertain the exact reason for the attack on Lokesh by his former friend Shankar and his father.
Lokesh's relatives told police that Shankar and Lokesh were once friends but later had a tiff over some issue which culminated in the attack today.
According to the victim's family, Lokesh was on the ground floor of the house when Shankar and his father barged into the house and hit him with beer bottles in his head and abdomen, said a police official.
He was taken to Dr Hedgevar Hospital where his condition was stated to be critical, police said.
Police have registered a case under relevant sections of IPC at Geeta Colony police station and efforts are on to nab the fahter-son duo.