My mother is widowed, what should she do as far as the house is concerned in preparation for the time when she is no longer with us?

You mother should consider doing an estate plan consisting of a will, a power of attorney, and an Advance Directive re health care decisions. She should consult an attorney about all of her options, which might also include putting children on the deed to the house now, creating a life estate deed, with or without powers, or deeding the property outright to a child or another now. Each of these options should be done only after consultation with a lawyer to fully explore all of the legal and familiar ramifications of each option. Please feel free to contact me to explore options.