A schizophrenic Manhattan man who dodged criminal responsibility for stabbing to death his wealthy philanthropist mother may finally have to pay for that heinous act with his inheritance.

A Manhattan judge committed Jonathan Schwartz, 44, to an upstate psychiatric hospital in March after a jury found him “not criminally responsible by reason of mental disease” for Barbara Weiden Schwartz ­Fischler’s murder in 2011.

Now Jonathan’s father, who was divorced from ­Fischler, is suing his son.

Steven Schwartz is also suing on behalf of his second son, Kenneth Schwartz, who committed suicide in 2013 after learning that his stepdad, Burton Fischler, gambled away nearly $6 million of Barbara’s fortune on risky stock-market “short sales” as executor of her estate.

There was only about $700,000 left in Barbara’s estate in 2013.

Now Steven Schwartz will get Kenneth’s share of whatever money he may win in the civil case against his committed son.

Daniel Gotlin, Jonathan Schwartz’s defense attorney, declined to comment except to say, “This is a family tragedy.”