Claim of maintenance by grandson from his divorced mother

My son and my daughter-in-law were divorced in the year 2001 and the custody of my grandson was given to my son by his wife at the time of divorce. Then my son died in an accident in the year 2002. As such, I am de facto guardian of my grandson. Now my grandson has attained the age of 16 and for his higher education I would like to claim maintenance from his mother who is earning handsome amount apex. Monthly 35000/-. I am retired govt. officer and maintain my household and education expenditure of my grandson from my pension. Can my grandson claim maintenance for his higher education from his mother who is non resident parent and still unmarried living with her mother.