Baidyanath Biswas, a farmer, recently sold some trees for Rs 90,000 and his son Abodh wanted a share of the money but his father refused, a police officer said.
An angry Abodh allegedly poured petrol on his father while he was sleeping and set him on fire at Rabanbar village under Ranaghat police station area on Friday night.
His mother Saraswati, who was sleeping on the same bed, suffered burn injuries while making an effort to save her husband.
Abodh too was injured trying to save his mother, the officer said.
All of them were taken to Ranaghat Anulia Hospital, where Baidyanath was declared brought dead, he said.
Baidyanath's other son Subodh lodged a complaint against Abodh at the Ranaghat police station.
The officer said Abodh, who suffered 50 per cent burns, would be arrested after he is released from hospital. Baidyanath's body was handed over to his family after post mortem.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)