No you cannot unless you buy the car in your brother's name.
NCB belongs to a person not the car.
Let other insurance experts advise.
Cheers,
Anshuman
Let me introduce myself here. I am a Software Professional making software for Insurance Companies for last 7 yrs. So I have good amount of insurance knowledge but not associated with any insurance company. So I can tell you the rules very well.
Anywhere in this planet, insurance NCB is tagged to the insured driver. So NCB is applicable whenever one buys a vehicle and gets insured in his name. BUT in India, they have a peculiar rule! One has to sell the car to avail NCB benefit to the newly purchased vehicle. The process is at first you sell your car (you can sell it to anybody in this planet - someone unrelated to you, your relative/wife/childern (if children are > 18 yrs)). Then you will have Form 29, 30, Sale Deed, Money Receipt of your sale. Submit them to your current insurance company, and ask them to issue an NCB certificate. In India NCB certificate will be valid for 3 yrs. from the date of sale of your car. You may/may not ask for cancellation of your insurance policy effective the date of sale of your car. If you ask for cancallation, you will get bacck premium paid on pro-rata basis. For reader's interest, I am writing here what will happen to the buyer of your car then? He should have contacted the insurance company intimating the sale and pay the differential premium, if any, to the insurance company. If you cancel insurance, insurer will intimate your buyer about that and collect the money they have returned you. Anyways, what happens to buyer is not your headache until you sell it to your friend/relative.
Now when you buy insurance for your new car, produce the NCB certificate to avail NCB in your new car.
This process has an in-built disadvantage of of having days when you do not have any car. I you don't like it, buy full premium for your new car. Later you sell your old car, get NCB certificate, and send the same to your insurer to claim pro-rata premium back for NCB. But your registration will cost more in this case since you are buying second car in your name. That money, I think not refundable by RTO (other forum members can correct me here if I am incorrect).
I have written the whole process clearly here, please go through carefully and see how you can apply these laws in your favor.
In case of any question, please post here, I'll try to answer.