Hi thank you very much for your advice. Eventually it is not practice to give such helmets it seems. It will be a challenge to find some shop in India. But I will use the website you gave and will try to solve my problem. Thank you very much.
I have attached a web address for a company that sells what you are looking for, but your mother's brain surgeon should be able to give you all the answers you need and also a company or store that sells them where you live in India.
http://www.rehabmart.com/category/Protective_Helmets.htm