Can something be done to stop mom’s transfer to another home care?

If this is an Oregon case, the court cannot make a son the agent under a POA or health care representative. The court could appoint him guardian, but that is a court proceeding you could object to.

You need to obtain the services of a conservatorship litigation attorney to investigate and bring the necessary petition in probate court to stop the son from moving mom.

Court cannot appoint a DPOA or MPOA, what a court can do is have Mom declared incompetent and have a guardian appointed. ?This is generally not a quick process, although a temporary order can be done on an emergency basis. ?The court will want evidence, this is generally a report by a physician or a care agency with experience in dementia or testimony of incompetent behavior (report of the professionals generally has more weight than testimony of family members who often have an agenda which is slanted toward not allowing parent to spend the parent's money and depleting an expected inheritance). If no one has been appointed guardian, start the process and have a group of siblings nominate a guardian. ?Be warned when some siblings favor one guardian and other siblings favor another, courts often appoint a lawyer that is picked by the judge and LOTS AND LOTS of money will go towards legal fees.

Your summary is confusing. A court does not make anyone POA. That had to have been done by your mother, when she knew what she was doing. Since your brother appears to have POA, the best thing you can do is to try to keep the line of communication open with him and make sure that your mother knows that you are there for her and will support her in any way that you can. Further court proceedings would not appear to make much sense, under these circumstances.