Estate Law Questions? Ask an Estate Lawyer.
Thank you for your question. I look forward to working with you to provide you the information you are seeking for educational purposes only.
No, that is not true that it cannot be released without probate. Personal property is something that generally only goes through a small estate process, most times unless there is a particular heir being disagreeable no probate is done. The value of this property is not even worth a full probate. So you can do a small estate affidavit as the sister and you can file that in court and then distribute it to the heirs (see for sample of the affidavit, which you could get from the probate court: https://s3.amazonaws.com/uslf-previews/ME/ME-ET10.pdf).
So she is not being completely reasonable and what she is saying is not completely true.