A good trademark attorney can see the forest for the trees -- which only comes from experience in the field (which is true for all fields) -- and who has one eye on the practical business reality of the situation while the other is on the specialized trademark nuances of the situation.
Moreover, a good trademark attorney has both litigation and transactional experience, the latter including experience in negotiations with marketplace participants, with the Trademark Office registration process, and with the rulings and procedure of the Trademark Trial and Appeal Board. Someone (like me) who teaches in the field is normally well qualified.
Though I'm not taking on new clients at the moment, I can refer you to other qualified attorneys in Sacramento who can assist your Dad. E-mail me offline.
Besides experience in the transactional, litigation, and practical aspects of TM law, I'd give preference to any lawyers who formerly have worked for the USPTO. They know all the secrets about getting an application through.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
An additional suggestion is that you can check their ratings by way of Martindale-Hubbell, a well-regarded attorney directory. If the attorney is "AV" rated, this is considered the best rating available.
DISCLAIMER: THE FOREGOING IS NOT INTENDED TO BE LEGAL ADVICE NOR DOES IT CREATE AN ATTORNEY-CLIENT RELATIONSHIP.