Will a family group healing help resolve the karmic entanglements, especially dark cordings from the departed grandmother to my client?

This has been done by your channel in arranging for a group cleansing, as that was also important to enable her spirit to be rescued. Past difficulty she participated in was a component, directly, in her being held back from progressing once she left the body. This also illustrates the unity of human souls, which is how things are organized. No one is an island; all are interconnected whether they see this or not. Even the most secluded and reclusive individual has karmic interconnections with many, many, others if only from the past, and those connections will have an influence on everything that happens or does not happen. And it all represents a healing need that can be addressed and will help all involved become free from hindrances of old business acting as a kind of anchor, slowing human progress individually and collectively.