He's disowned his own father.

His own father therefore, disowns him for ever and ever, as a unnat'ral young beggar.' He had pushed away his plate.

With the natural need of a strong rough man in anger, to do something forcible, he now clutched his knife overhand, and struck downward with it at the end of every succeeding sentence.

As he would have struck with his own clenched fist if there had chanced to be nothing in it.
'He's welcome to go.

He's more welcome to go than to stay.