What is the ruling on visiting shrines and graves with the intention of seeking blessings and asking for needs to be fulfilled, and what should I do to free my closest relatives from this polytheism prevalent in Algeria?

Seeking the fulfillment of needs from the deceased, supplicating to them instead of Allah, and believing that they possess the power to harm or benefit, is major shirk (polytheism). Visiting graves for blessings and supplicating at them are blameworthy innovations (bid'ah) and a means to major shirk. Rather, they should be visited for admonition and to supplicate for the deceased and seek forgiveness for them. It is not permissible to prevent a girl from marrying a suitable man, even if he is from outside the tribe. Those who engage in these practices should be advised gently and kindly, and reminded of the evidence that Allah alone is the One who exclusively possesses the power to benefit and harm.