My brother suffers a serious disease that makes him unable to speak. But he makes mention of Allah with his heart at the times of Salah (prayer). He stutters when he recites Qur'an. Should he give up Salah until he recovers or should he perform Salah in this condition?
Your brother should perform Salah in the manner that suits his circumstances and according to his ability as long as he is sane. Allah (Exalted be He) says,
So keep your duty to Allâh and fear Him as much as you can
It was authentically reported that the Prophet (peace be upon him) said,
When I command you to do anything, do of it as much as you possibly can...
(Part No. 8; Page No. 81) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.