Therefore, the righteous friends are those who remind each other about the Hereafter and encourage each other to perform good deeds. They do not cheat each other, and certainly do not encourage each other to doing something forbidden or unjust.
A pious friend is one would advise you and warn you if you do a forbidden act because he wishes you to be religiously well. Prophet Muhammad peace be upon him said what means:
<< The believer is like a mirror to his brother >>
Meaning he warns and advises his brother until his situation is corrected. The mirror is used to reveal that which we dislike in ourselves in order to be removed or corrected. The prophet likened the believer to the mirror in terms of recognizing the faults in his brother and guiding him for the sake of Allah until that fault is corrected.
The pious friend is the one who loves you for the sake of Allah, not because of worldly matters, your money or because he wishes to marry someone related to you.
Those who truly love each other for the sake of Allah shall be under the shade of the throne (the ceiling of Paradise) on the Day of Judgement, where the prophets and martyrs will be pleased to see them.
In conclusion my dear brothers, if you know that your Muslim brother has not learnt the matters of the religion, has not learnt the obligations and is not aware of the forbidden matters, then it is your duty not leave him the way he is and to advise him with wisdom for the sake of Allah. And if you wish to visit your brother, then visit him with sincere good intentions hoping for Allah to reward you on the Day of Judgement.