What is meant by "al-daq" for children, and is it permissible to do it for a daughter whose family suffered the death of two children after her birth, taking into consideration the belief of some women that the girl's "qareen" (jinn companion) does not like subsequent children from her? What is the extent of the validity of this statement and its legal ruling?

What the questioner mentioned about the custom of 'daqq' (beating drums or making noise) for children is a forbidden innovation (bid'ah), whether it is the 'daqq al-subu'' (seventh-day celebration drumming) or 'al-zar' (exorcism ritual drumming). This is because in both cases, it falls under the category of appeasing devils, which is forbidden by Islamic law and enters into the realm of shirk (definition) (polytheism), due to Allah's saying: ﴿And indeed, there were men from mankind who sought refuge in men from the jinn, so they [the jinn] increased them in burden [or sin and transgression].﴾ (Al-Jinn: 6).