Autistic nephew (4) hit my 4 year old daughter, so my daughter grabbed his hand and bent it backwards. Now my sister is mad?

I’m sorry but 4 years olds regardless of them having autism or not do not know what the hell autism is. My sister is mad because my daughter defended herself.. which is what I teach her to do when someone hits her. My sister is mad that I didn’t discipline my daughter for essentially defending herself just because my nephew is autistic. Thoughts?
Updates
+1 y
He’s on the spectrum. Has not been officially diagnosed autistic.
Updates
+1 y
She tried to discipline my daughter and tell her to leave him alone.. and I went back and said that she said he hit her so.. when I walked back to my room, my sister said some shit I couldn’t hear but obviously disagreeing with her son getting back what he dished out.
Autistic nephew (4) hit my 4 year old daughter, so my daughter grabbed his hand and bent it backwards. Now my sister is mad?
Post Opinion