Obtaining an ex parte TRO as a precursor to a DVRO is relatively easy, as long as the petitioner makes a colorable allegation of "abuse," pursuant to FC §6200 et seq. It is also relatively easy for the petitioner to include “other persons to be protected” on the DV-100 application, which is how your son-in-law became a party to this matter.
Because this process is easy and free, the petitioner often becomes greedy in their quest for injunctive relief, and lists “other persons” just because they can. While the petitioner erroneously believes that by doing this they are establishing a stronger case, the reality is that their embellishment provides someone like me with an additional argument that the entire petition is itself exaggerated and or concocted.
If you want a real chance at prevailing, retain an attorney to defend this as soon as is possible.
There are not enough facts to give a well informed response but with what you have written my answer is yes she can include her new husband. You are allowed to request protection for all those living in your household (and as one responder noted even pets). This does not mean that when you appear at the hearing the judge will make the order permanent, as I said there are not enough facts here to give a more informed response.
Speak with a attorney in your area that has experience with Domestic Violence matters.
Note this answer does not constitute legal advice, and should not be relied on. Each situation is fact specific and court specific, and it is not possible to evaluate a legal problem without a comprehensive consultation and review of all the facts and court pleadings filed in the case. This answer does not create an attorney-client relationship
The domestic violence restraining order act permits blood relatives to file restraining order in family court and not file the civil harassment in civil court. This means that the standard of proving theirs case is much lower in family law court the standard is preponderance of the evidence and in civil it is clear and convincing a much a higher standard and thus more difficult to prove your case. I believe up to first cousins is the blood relative limitation