Will the 8-year-old girl a viewer told me about, who fears her mother dying, be helped by doing LHP and DSMR sessions for her? Is that fear old karmic trauma, or was the loss of relatives in the current life a causal factor in raising this fear?

Both things are true. She has some deep karma from prior lifetimes when her mother died and left her unattended at a young age and this resulted in tremendous suffering. That karmic legacy was reawakened and inner fear triggered by her resonating with the loss of other relatives, as you were told about. So it was not just that she saw family members die, but there was a karmic landmine waiting to explode if stepped on. So that was a perfect karmic setup to reawaken the prior experiencing and to fear it coming again. This does include a karmic potential for a replay event between mother and daughter in this life. And that is what you were tuning into as you talked about this situation and cautioned about not opening a can of worms with the mother, as that would likely cause some misgivings and potentially much inner fear. In actuality, this is already being stirred up within her deep subconscious because the daughter has brought this to her attention and it is part of the anguish about the daughter that her deep subconscious feels caught in a trap, and that might well turn out to be so without a healing intervention. So this will be a blessing to do the work you proposed for the two of them, because it may well turn the tide and prevent a repeat creation of dual casualties.