If you try to use Islam as a means for them to give you financial support while they still resent you, you will not only increase their resentment for you but also their resentment of Islam.
If it was earned wrongfully, such as interest, its equivalent amount should be given in charity (sadaqa).
If the amount is large, then create a schedule that allows you to fulfill the amount slowly.
This practice is valid. When a Muslim recites the testimony of faith (shahada), it is an act of worship. It is not just recited due to fear of polytheism. A ruling of polytheism is only applied upon an action done with the knowledge of it being a polytheistic action.
Reciting the testimony of faith (shahada) is a righteous form of remembrance. The scholars mention that its repetition has many virtues. Among them are;
(Kasani, Bada`i al-Sana`i)
This child is your ‘brother in Islam’. You should grant him the same rights you would grant your neighbor or friend, such as helping them when they are ill, replying to their greeting, etc.
Share this portal with your friends and family & beloved ones.
On the weekly compass newsletter