For further study about maintenance we have to look into Hindu Adoption & Maintenance Act, 1956. I'm supplying the excerpts below for your kind consideration:
18) Maintenance of wife
(1) Subject to the provisions of this section, a Hindu wife, whether married before or after the commencement of this Act, shall be entitled to be maintained by her husband during her lifetime.
(2) A Hindu wife shall be entitled to live separately from her husband without forfeiting her claim to maintenance -
(a) If he is guilty of desertion, that is to say, of abandoning her without reasonable cause and without her consent or against her wish, or of willfully neglecting her;
(b) If he has treated her with such cruelty as to cause a reasonable apprehension in her mind that it will be harmful or injurious to live with her husband;
(c) If he is suffering from a virulent from of leprosy;
(d) If he has any other wife living ;
(e) If he keeps a concubine in the same house in which his wife is living or habitually resides with a concubine elsewhere;
(f) if he has ceased to be a Hindu by conversion to another religion ;
(g) if there is any other cause justifying her living separately;
(3) A Hindu wife shall not be entitled to separate residence and maintenance from her husband if she is unchaste or ceases to be a Hindu by conversion to another religion.
21) Dependants defined
For the purposes of this Chapter "dependants” means the following relatives of the deceased:
(i) his or her father ;
(ii) his or her mother;
(iii) his widow, so long as she does not re- marry
(iv) his or her son or the son of his predeceased son or the son of predeceased son of his predeceased son, so long as he is a minor:
PROVIDED and to the extent that he is unable to obtain maintenance, in the case of a grandson from his father's or mother's estate, and in the case of a great - grand son, from the estate of his father or mother or father's father or father's mother;
(v) his or her unmarried daughter, or the unmarried daughter of his predeceased son or the unmarried daughter of a predeceased son of his predeceased son , so long as she remains unmarried;
PROVIDED and to the extent that she is unable to obtain maintenance, in the case of a grand - daughter from her father's or mother's estate and in the case of great-grand- daughter from the estate of her father or mother or father's father or father's mother;
(vi) his widowed daughter :
PROVIDED and to the extent that she is unable to obtain maintenance
(a) from the estate of her husband, or
(b) from her son or daughter if any, or his or her estate; or
(c) from her father-in-law or his father or the estate of either of them ;
(vii) any widow of his son or of a son of his predeceased son, so long as she does not remarry:
PROVIDED and to the extent that she is unable to obtain maintenance from her husband's estate, or from her son or daughter, if any, or his or her estate; or in the case of a grandson's widow, also from her father-in-law's estate
(viii) his or her minor illegitimate son, so long as he remains a minor;
(ix) his or her illegitimate daughter, so long as she remains unmarried.
23) Amount of maintenance
(1) It shall be in the discretion of the court to determine whether any, and if so what, maintenance shall be awarded under the provisions of this Act, and in doing so the court shall have due regard to the considerations set out in sub- section (2), or sub- section(3), as the case may be, so far as they are applicable.
(2) In determining the amount of maintenance, if any, to be awarded to a wife, children or aged or infirm parents under this Act, regard shall be had to.-
(a) the position and status of the parties;
(b) the reasonable wants of the claimant ;
(c) if the claimant is living separately, whether the claimant is justified in doing so;
(d) the value of the claimant's property and any income derived from such property , or from the claimant's own earnings or from any other sources;
(e) the number of persons entitled to maintenance under this Act
(3) In determining the amount of maintenance, if any, to be awarded to a dependent under this Act, regard shall be had to.-
(a) the net value of the estate of the deceased after providing for the payment of his debts;
(b) the provision, if any, made under a will of the deceased in respect of the dependant;
(c) the degree of relationship between the two;
(d) the reasonable wants of the dependant;
(e) the past relations between the dependant and the deceased;
(f) the value of the property of the dependant and any income derived from such property; or from his or her earnings or from any other source;
(g) the number of dependants entitled to maintenance under this Act.
22) Maintenance of dependents
(1) Subject to the provisions of sub section (2) the heirs of a deceased Hindu are bound of maintain the dependants of the deceased out of the estate inherited by them from the deceased.
(2) Where a dependant has not obtained, by testamentary or intestate succession, any share in the estate of a Hindu dying after the commencement of this Act, the dependant shall be entitled, subject to the provisions of this Act, to maintenance from those who take the estate.
(3) The liability of each of the persons who takes the estate shall be in proportion to the value of the share or part of the estate taken by him or her.
(4) Notwithstanding anything contained in sub section (2) or sub section (3), no person who is himself or herself a dependant shall be liable to contribute to the maintenance of others, if he or she has obtained a share or part the value of which is, or would, if the liability to contribute were enforced, become less than what would be awarded to him or her by way of maintenance under this Act.