Hello and thanks for using Just Answer.
My name is ***** ***** am happy to assist you with your enquiry.
The majority of house deeds are now registered at the Land Registry, meaning that the Land Registry electronically store them and any member of the public can obtain a copy. Accordingly, the fact that someone may be holding a set of physical Deeds does not prevent a third party from selling.
Likewise, if your brother is holding the physical Deeds does not give him any "advantage" when it comes to any potential sale.
I note your brother's name is ***** ***** the Deeds, so if he did go ahead and sell the house, he would be guilty of fraud. The only way he would be able to sell the house during your Mother's lifetime is if the house needed to be sold to pay for any Nursing home fees AND your brother had been appointed as your Mother's Attorney.
You therefore have little to worry about concerning the fact he may be holding the Deeds.
I hope this helps but please let me know if you require any further clarification.