The problem is the statement Gibson and his son, the star of blockbuster films like "Braveheart" and "Lethal Weapon," are practitioners of an ultraconservative Catholic movement known as traditionalism. The small splinter group seeks to revive orthodox practices that were abandoned several centuries ago by mainstream Catholicism. .
There is no unified movement or group called "traditionalism". "Traditionalist" is a descriptive word applied to a very large variety of groups, movements, and tendencies, most of which are not schismatic. To say that "Gibson and his father belong to the same movement" is either simply false or intentionally misleading.
The question is what this group called "Holy Family" is. There are many lay groups in the Church (such as the Knights of Columbus or your local Catholic hospital or school) which may build private chapels and have masses validly and licitly celebrated, with the full awareness of the local bishop. On the other hand, if the title "church elder" which the article applies to a member of the Holy Family group is actually a term used by the group rather than made up by the writer, this raises a concern. The CRITICAL question is what the local bishop thinks, and the fact that neither of these articles made any attempt to call his office indicates to me that there is nothing schismatic or heretical going on and they are just trying to make Gibson look bad.