Does Tirmidhi's hadith mean that the righteous Awliya (saints) of Allah are alive in their graves and can recite the Qur'an, which might suggest the possibility of them hearing or us hearing them, and does this contradict what some groups do in deceiving people?

The hadith "It is the preventer, the rescuer; it saves him from the torment of the grave" is weak. The life of prophets and righteous people in their graves is a barzakh-like existence, the true nature of which is known only to Allah. There is no evidence in Islamic law that the righteous recite the Quran in their graves. The general rule is that the dead do not hear the speech of the living, except for specific textual exceptions such as the deceased hearing the footsteps of sandals after burial, or the slain at Badr hearing the words of the Prophet, peace be upon him. These are specific instances and do not imply their general hearing of all speech. The meaning of Allah's saying, "Indeed, you cannot make the dead hear," is that they are unable to respond to those who call upon them. The Sufi and Barelwi groups are innovators and contradict the guidance of the Prophet, peace be upon him, and the righteous predecessors.