What can I do if my sister lives in house with my son and if I will not do what she asks he will call the police claim for elderly abuse?

If your sister does not have any life estate interest and does not pay any rent, she has no right to live there while you are alive. Tell her in an e-mail or letter what in her behavior is very upsetting and detrimental to your son and you, and that she has to leave [state a reasonable time period] as she has no legal right to remain there. She is a guest and can be told to leave at any time, but is entitled to remove her possessions. Since the police probably will not help you evict her, and there is some disagreement by attorneys as to whether you can just kick her out, demand she pay rent and then give her a three notice for failure to pay rent. You can then get a judgment against her that she has to move and the sheriff's office will enforce that. Before you do the above, if you really believe she will claim elder abuse, write the agencies that handle those claims and tell them what is going on and she may, as revenge, report you. Your son should stop having any contact of any type with her so you both can testify he had no contact during a period she claims abuse.