It depends on what your parents' estate plan says about who controls the property that your father left behind. If he left it all to your mother, then what she
And if you are your mother's financial agent, acting under a power of attorney that she signed, it's your job to carry out her wishes--and you have no real say in what she does with her money and property.
If, however, your parents' estate plan left your father's share of the estate to your mother in trust, which is a common estate plan for married couples, especially those with sizable estates, then it's probable that your father's assets are already slated to go to you and your siblings when your mother dies.
does with it is her business, and not yours.