All of these acts were put forth under the leadership of Jawaharlal Nehru, and were meant to codify and standardise the prevailing Hindu legal tradition.
The Adoptions and Maintenance Act of 1956 dealt specifically with the legal process of adopting children by a Hindu adult, and with the legal obligations of a Hindu to provide "maintenance" to various family members including their wife or parents, and in-laws.
The only way of getting around obtaining the permission of the wife or of the wives is if she or if they are unsound, if they have died, if they have completely and finally renounced the world, and if they have ceased to be a Hindu.
The child cannot be the age of fifteen or older, unless again it is custom or the usage is applicable to the involved parties.
[3] A Hindu wife is entitled to be provided for by her husband throughout the duration of her lifetime per Section 18 of HAMA '56.
The only way the wife can null her maintenance is if she renounces being a Hindu and converts to a different religion, or if she commits adultery.
This separation can be justified through a number of different reasons, including if he has another wife living, if he has converted to a different religion other than Hinduism, if he has treated her cruelly, or even has a violent case of leprosy.
Additionally, if the widow remarries then her late husband's father-in-law is not legally bound by this Act anymore as well.
If any debts are owed by the deceased, then those are to be paid before the amount of maintenance is awarded or even considered.