MY brother is a bit weak in Eemaan. He prays regularly but isn't interested in other things. He sometimes misbehaves with mom and I don't like this. I've also seen him do certain silly things that a Muslim shouldn't. Advise me please.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

You have to know that as long as your brother is always performing his prayers, this is a good sign. Many people call themselves Muslims but do not perform any prayers, or pray but are not steadfast in prayer. So you have to advise him as advising is a part of our religion. This is indeed one of the greatest acts of keeping good relations with kin. Begin advising him by praising his seriousness and continuity in performing prayers. Remind him that the most important benefits of prayer is that it prevents the person who prays from committing sins, as Allaah says (interpretation of meaning): {…and perform "As-Salat" (Iqamaat "As-Salat"). Verily, "As-Salat" (the prayer) protects one from Al-Fahshaa' (i.e. great sins of every kind, unlawful sexual intercourse, etc.) and Al-Munkar (i.e. disbelief, polytheism, and every kind of evil wicked deed, etc.)…}[29: 45]. Then you should mention some of his mother's rights on him, as she is one of the means for his existence. Indeed she is a reason he may be admitted to Paradise if he is kind and dutiful to her, or a reason he may enter Hell-fire if he cuts relations with or mistreats her. Please refer to Fatwa: 85542.  Finally, please consider the following matters:

Firstly, you have to admonish and advise him with good and soft words so that he may take heed.

Secondly, you are not obliged to advise him yourself, it is permissible to inform whoever can influence him to deal with it.

Thirdly, it is permissible to desert him (cut relations with him) if he does not take heed and if you think that he will benefit by being cut off. However, if you think that cutting relations with him will lead him to committing more sins, then he should not be cut off.

Allaah knows best.