It is my understanding that it is pretty unusual, subject to some exceptions, to put a defendant (whether innocent or not) on the stand as it's just too easy to get tripped up by a skilled prosecutor in cross-examination.
In addition, it seems TM has decided he is going to take the fall for the two of them so it seems to me that it didn't matter whether he messes up in cross-examination or not.
He has admitted to hitting several times JC in full testimony before the jury, including critically IMHO, dealing JC the fatal blow which killed him. He has fully shielded her and IMHO, has deliberately put himself first and foremost in the frame for the murder.
As she has said nothing, other than the statement she made (which I think Stephan pointed out) that she tried to hit JC but was unsuccessful, there is only circumstantial evidence against her (no direct evidence such as finger prints, etc). I would assume under NC State law that as this evidence is so overwhelming that this is still sufficient to convict her. But I don't know to what degree.
Irishmartin asked does it matter who pulled the trigger? I think it does. My understanding is that it is usual for whoever to have dealt the fatal blow to be convicted of murder and two people can't be convicted of the murder of the same individual (subject to certain exceptions which do not seem to apply here). Those aiding and abetting can get a similar sentence despite the lesser charge which she may be where it ends up with her. We all know she did it, it's just the evidential rules are complicated and tricky as they are designed to protect innocent defendants.
Also, as an aside also, a will is usually automatically revoked by a later marriage. So if you have made a will and subsequently got married, the original will automatically be revoked. I am not sure if that is the position under NC State law but it is a common principle.
In any event, the results should be out shortly.
As a final note, I don't think TM did himself any favours on the stand. It's also a little transparent that how, within hours of the media reporting TM and MM were unemotional at the trial, they both break down in tears and weep. It does amaze me that with all of their superiority and arrogance, there are no lows to which that family will not stoop.
All IMHO of course.