unless its a family member, you should be trained. I agree that family members are the hardest ones to manage, but it any one needs more information, see Roslyn Carter Institution of Caregiving in Atlanta GA on the web. its an excellent place for resources and information on caretaking, Caregiving, and being a Live-in-aide.
There are varying degrees of caregiving. We are currently working with elder care attorneys and we visit our aging parent at a nursing home daily to every other day to check on our ailing mother. Since I am POA, it is important to me to let my presence be seen at the nursing home so that proper care is occurring and if my mother needs anything she does not have to wait to see me. I also handle all medical, appts. Banking, bill payments. You have time and out of pocket gas expenses plus if time is short going to see her, to grab a meal on the run. You can have a caregiver agreement drawn up and there is a allowable amount per hour that you can use to pay your brother for time spent helping to cover the time and gas, etc.
If your brother is looking to get some kind of financial help can get it through a veterans site if his father was in the service. They send forms to be filled out explaining what his duties are with your mother. I think a doctor has to sign the form. Hope this helps.
Unless there is a VA pension involved or some type of payment being made I'm not sure why you would need a letter from a doctor. If she is giving him money to care for her then, yes, there needs to be documentation for Medicare that it was a medical need and not just a gift. They look back five years when it is necessary to place them in a nursing home and any monetary gifts are looked at.
I'm confused by your question also. A caregiver is anyone who comes into a home or lives there and provides comfort and aid to the patient. This could be in helping with household chores, shopping, bathing, dressing, etc. Generally, relatives whether they live there or just visit to do the caregiving are unpaid volunteers. A doctor needs to approve the care and payment of a caregiver sent by an agency for medical care. In your brother's case, no doctor's statement of need is necessary for him to live there and help out.
Ferris1 is correct, although if you're interested in regulatory compliance for something specific, call the Dept of Aging in your state and ask what the legal/regulatory definition is.
Your question is about caregiving I believe. A "caregiver" is one who gives care to another. There is no prerequisite other than the person doing the "care" be kind, loving and present. You do not give any reason for your brother living with your mother so I will not comment further since I have no idea what you are really asking. Please provide more details.
The MD must substantiate the need and what date the need began. The brother must prove he actually lives there and that he is not being supported by her. For example, his driver's license and voter registration should show the same address and what date the change was made to show him living there.
its an excellent place for resources and information on caretaking, Caregiving, and being a Live-in-aide.