Advice on correcting hurtful words

How would you go about correcting a 10yo saying hurtful things to other children? 

it’s not so much blunt talking hurtful, but things like telling another child their step father doesn’t care about them. 

the other child also has additional needs and takes things very literally and dwells on things for a long time. 

If it is mentioned that the comments were hurtful, a “tantrum” is thrown and then the ASD child says they want to go home and not see their father any more. 

We have so far tried to ignore the comments, but it is causing a lot of bad feeling with the other children. They also have friends on the spectrum who are quite “straight talking” and that is understood, but it’s difficult for them to understand these kind of comments. 

how do we explain to the other child/ren(11) why they are being so mean and how do we explain to ASD child, that they are causing distress with their comments?