• Legal rights of property purchased jointly by parents

I have a friend by name Kumar. He has a younger brother by name Ravi. Kumar's father had purchased a constructed home in 1981 along with his mother (i.e. the property is jointly held by his father and mother). Kumar's father expired last year. 

Kumar is married and a good chap. He is the one who takes care of his family (mother, brother and his wife). Ravi is not married. Ravi goes to work but will not spend a penny for his home and keeps troubling his mother for more money when Kumar is not around. He is highly irresponsible and keeps quarreling with his mother telling that his father has not made enough wealth for him.

Now Kumar wants to construct a home by demolishing the old home. He is willing to take care of the complete expenses of the construction and wants to see his mother in the new home. He does not want his brother to make loan on the constructed home. 

Now these are my queries:

1. After the death of his father, is only her mother the legal heir or is it the son's too? If sons are also legal heir, how to avoid the misuse of home by the second son?

2. Can his mother make a will in such a way that the rights of selling the home or borrowing money by pledging home should not be given to the younger son Ravi. Ravi can just stay and enjoy the property but should not treat this as his asset for monetary benefits.

My intention is that Ravi, the second son has to change and lead a responsible life rather than pestering his mother and that later after his mother, he should not be a problem for his brother. Kindly advise. Thanks in advance.