When a person initially goes to the doctor checking to see if they have Alzheimer's, what tests will a COMPETENT Doctor run?

My brother-in-law has alzheimer's and apparently has had the sypmtoms for a few years. He still dresses himself, eats on his own, takes his meds and even drives his truck (because my sister can't find where he hides his keys). His biggest irritation to my sister is asking the same questions, over and over and over again. I guess my question is this, when a person initially goes to the doctor checking to see if they do have Alzheimers, what tests will a COMPETENT Doctor run, i.e. MRI, etc. or do they just initially ask the routine, date of birth, who is the President, on and on. They live out of state so I only get feedback via internet and it is always the same complaint from my sister about the question asking and his temper which at times is scary. She challenges him all the time as she has a short fuse which in itself can be dangerous and self defeating. It took her three years of my getting after her to join a caregivers seminar because she said she didn't want to hear from other people the same problems she has. I guess you get the picture, if it weren't that they have lots of pets, which my sister loves, she would have left home a long time ago. This is a very sad situation and very stressful for me to always hear about since we just lost my Mother after my caring for her 24/7 for ten months and realize that no one asks for these health problems, and even through the most difficult times that I had with my 96 year old Mother who was disabled, at the end of the day I could always find a blessing. There were many days I had to look hard, but they were always there especially if I put being a martyr on the shelf. What diagnostic testing was done for your loved one who has Alzheimers? If you don't do base testing such as an MRI, how on earth do you know about the progression mentally other than the affected persons actions? God bless all of you who are care givers and God bless the ill person. Neither one of you asked to be in this situation, but don't exclude God in your life. Remember, he is still in charge!