Reference: as-Sahwah al-Islaamiyyah – Question 63, Page 199
Question: How do we combine [the acts of] forbidding an evil, maintaining ties of the womb (family ties) and da’wah to Allaah (Subhaanahu wa Ta’aala) with leniency and softness [all] at the same time?
Response: A wise person is able to combine [the acts of] forbidding an evil, maintaining ties of the womb and da’wah to Allaah with leniency and softness. So he forbids [an evil] sometimes and remains quiet over some things which he is able to sustain along the path to that which is good.
We offer an example [here]: There is a man whose father does some evil deeds, whilst he assists him in certain permissible issues. Along with this, he (the son) reminds him of some things and says to him, for example:
If a person does such and such, then his eemaan decreases, and quite possibly he may be punished in this world before the Hereafter.
And it is possible his father may realise his son is implying him, and may take caution [against such acts]. [As a result] he would love his son for being lenient and not being so upfront, and Allaah (Subhaanahu wa Ta’aala) may well guide him.