Your mother is settling well into her new life as a retiree, but because her heart chakra is consistently disconnected from her lower chakras, her lungs and throat are not well. She is tired because she is not grounded or drawing energy from her lower chakras as she should be, but relying merely upon her upper chakras, which cannot fuel the whole body effeciently. She needs to meditate and breathe through her feet. When she is in her sacred garden she should sit with her feet on the ground and breathe through her feet, as if she is one of the trees of the garden. If she finds this boring, as she tends to find all grounding exercises, she can also invite the fairy spirit and tree spirit of the garden to enter her body and fill her with their radiance. She will be well in no time if she makes this a nightly part of her routine. She should face east, for that is where she draws her energies best, and breathe through her feet for at least 5 minutes at a time.
She will be well, as are you.