If he can't get the elder, he will be only a little less happy if he gets the younger.
If Trump Jr broke the law, then he deserves to be “got†- or is it passé now to expect people to pay the consequences for breaking the law? Or is that just a privilege limited to those whose surname is “Trump�
And FWIW, IMHO he won’t indict Trump except for something as clear as videotaped proof of Trump killing someone. He’s almost certainly following the model that was used with Nixon: building a roadmap that Congress can then follow if it musters the political will to impeach.
What Mueller is doing is making sure that the president is seen to be surrounded by criminals whom he willingly chose to associate with. The question then becomes whether the Congress has the political will to impeach under those circumstances.