Police fatally shot a man who viciously stabbed his disabled mother at their Long Island home on Mother’s Day, according to authorities and sources.

Southampton cops responded to an “escalating domestic situation” at a Riverhead residence on Topping Drive around 2:40 p.m. on Sunday, according to the Suffolk County Police Department.

When officers arrived at the home, they found the son actively stabbing his mother, sources said.

The unidentified man was shot and killed by officers with the Southampton Town Police Department after he refused to put down the knife, according to sources and police.

The mother, who sustained several stab wounds in the harrowing attack, was rushed to a local hospital with serious injuries, sources and cops said.

She is confined to a wheelchair and was described by neighbors as a quiet woman who suffered years of domestic abuse. She had triplet boys, with at least two of them suffering from mental illness, WABC reported.

The woman, who was not identified, made at least one 911 call on Sunday, stating she had become afraid of her son, sources added.

Three Southampton police officers were also taken to a local hospital and treated for unknown injuries. They have since been released, according to authorities.

Detectives from the New York State Attorney General’s Office responded to the scene, cops said.

An investigation into the incident remains ongoing.

The Southampton Police Department did not immediately respond to The Post’s request for comment.