One-on-one counseling, in-person or virtual,
with a doctoral level clinician. Some relationships last just a few sessions while other's last years.
Some relationships improve with simple commuication skills, some relationships require a little more.
Testing for ADHD, Autism, pre-surgical evaluations, intelligence/academic, personality/emotional/mood, and many others. To confirm or refute diagnoses, testing can help quantify your questions.
With the entire family unit in attendance, everyone has an equal opportunity to express ideas and develop a better perspective and contribution each individual has to the family unit.