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.
First of all, it should be noted that affection and keeping good ties with all Muslims are religious requirements, and this matter is more confirmed among kinship as Allaah ordered us to keep ties with kinship and severely threatened those who severs such ties. In this regard please refer to Fatwa 83031. Furthermore, enmity and cutting relations among the brothers without a sound religious reason is a sin and a reason of being prevented from the Mercy of Allaah. The Prophet said: "The gates of paradise are opened Mondays and Thursdays and every slave of Allaah who does not associate any partner with Allaah has his/her sins forgiven except the person who has an enmity with his Muslim brother. Allaah Says: "Delay these two until they reconcile. Delay these two until they reconcile. Delay these two until they reconcile." [Muslim]
If your brothers are as you mentioned and they do not have a sound reason for doing so, then they are wrong. We advise you to be patient with them and invoke Allaah earnestly to rectify their affairs. Nonetheless, you should know that countering their wrong with good treatment and kindness are reasons which lead to affection. In this regard, please refer to 87510.
You should advise them in this regard in a good and nice way, and find the reasons for such enmity and then try to solve the issue. Also, you may seek the help of the pious and righteous people to reconcile between you, as Allaah might make this reconciliation happen thanks to their efforts.
As regards their behaviour with their mother, if this is confirmed without them having any religious reason, then it is very rude, as she has a great right on them, and they are obliged to be kind and dutiful to her. So one should advise them in this regard.
Finally, it should be noted that if the mother does not have money to spend on her, then her children are obliged to spend on her each according to his ability.
Allaah Knows best.