To protect a mark, you have to do more than file a registration and buy a domain. You have to actually use it "in commerce" which is a rather stringent legal standard that changes on a per industry basis.
It isn't clear that he is actually has been "using" the name in the manner required by trademark law, and you can't just have "token use" and keep a TM forever. It doesn't seem like any products are actually for sale under his mark, and it isn't being marketed, so it seems like he isn't using it "in commerce" in the way that TM law requires.
Second, if you search the TM database there are approximately 40 registered names with "Case" in it, in the area of legal software; ergo it is a very common term in the legal software field. The standard for TM infringement is "likelihood of confusion", in other words, is a typical consumer going to be confused about the origin of the software.
Even IF his marks were being used in a way which satisfied the "use in commerce" test, with all those Case* names out there there is no likelihood of confusion. In other words, if a consumer of legal software services is looking for his Case* mark, they are not going to be confused by the other 40 Case* marks, because consumers of legal services know that "Case" is a common term in the field and not all products named "Case*" are owned by the same person.