You might try finding the link to this clip..in China,
It's not the same but along the same lines
The use of the fingers to help focus one’s intent is common in certain Taiji lines.
It’s a way of avoiding getting around using the body directly or stuck at the contact point.
The OP video explicitly demoed this aspect.
You might find it similar to Aikido’s “unbendable arm,” where ki is projected beyond the contact point so the body organizes without local effort.
In Taiji, the finger is used to as though pointing, to extend the yi (intent) joined with qi, expressed through the body acting as a conduit. At first, the body’s role is emphasized to help you align the structure creating a focal point. Over time, it becomes the integration of yi, qi, shen — the three internal harmonies (nei san he) — working together with the three external harmonies (wai san he) so that intent, energy, and structure act as one.