@ Author,
A fantastic que. after a very long time;
1. The Act is applicanble to your sister and who says it is not applicable !
2. S. 2 of the Act specifies the persons to whom the Act is applicable. Clauses (a),
(b) and (c) of sub-section (1) of S. 2 make the Act applicable to a person who is a Hindu by religion in any of its forms or developments including a Virashaiva, a Lingayat or a follower of the Brahmo, Prarthana or Arya Samaj and to a person who is a Buddhist, Jain or Sikh by religion. It is also applicable to any other person domiciled in the territories of India who is not a Muslim, Christian, Parsi or Jew by religion. The applicability of the Act is, therefore, comprehensive and applicable to all persons domiciled in the territory of India who are not Muslims, Christians, Parsis or Jews by religion.
3. The term “Hindu” has not been defined either under the Act or the Indian Succession Act or any other enactment of the legislature till date as per my detailed study of words and terms in various Acts / Codes / Statutes and some independent legal studies !
4. However, just check Constitution (Scheduled Tribes) Order, 1950 as amended by Scheduled Castes and Scheduled Tribes Order (Amendment) Acts 63 of 1956, 108 of 1976, 18 of 1987 and 15 of 1990, both your sister and your Brother in Law tribes to which the parties belong are specified in Part XII or not?.
5. My further views is that now, in the absence of a notification or order under Article 342 of the Constitution SC / ST are deemed to be Hindus. Even if a notification is issued under the Constitution, the Act can be applied to Scheduled Tribes as well by a further notification in terms of sub-section (2) of S. 2 of the Act.
6. I think the mental block in you developed may be because of some “customary” practice followed by both and or either parties to suit which you have not mentione din your brief (that is where I am confused) however if she married him under Hindu Marriage Act then no custom can create an offence as it essentially deals with the civil rights of the parties and no person can be convicted of any offence except for violation of law in force at the time of commission of the act charged.
7. Custom may be proved for the determination of the civil rights of the parties including their status, the establishment of which may be used for the purposes of proving the ingredients of an offence which, under S. 3 (37) of the General Clauses Act, would mean an act or omission punishable by any law by way of fine or imprisonment. Article 20 of the Constitution, guaranteeing protection in respect of conviction of offence, provides that no person shall be convicted of any offence except for violation of law in force at the time of commission of the act charged as an offence. Law under Article 13 clause (3) of the Constitution means the law made by the legislature including intra vires statutory orders and orders made in exercise of powers conferred by the statutory rules.
Sum total of such lengthy write-up (I admit) is that she may go ahead and file S. 24 HMA petition in a Family Court (even before A.P. Court) and under Jurisdiction she may mention above paras and I doubt if Family Court can refuse admission of her legitimate maint. needs even being from ST / SC ?
Subject experts may correct me and I am offering to stand corrected to extent of this post only.