The family did not indicate that they needed assistance upon purchasing the ticket. They did not check the boxes.
If she refused assistance after getting in her powered wheelchair, she is then on her own. It is the fault of her and her family, not Huntleigh nor Alaskan Airlines.
That is just it. The family paid for it. Remember this is an old, sick woman. Go with what the family paid for. The woman did not pay for the service her family did so there for she has no authority to end it