How does one with a continuous condition (like urinary incontinence or non-menstrual vaginal bleeding - mustahada) perform ablution?
A person with a continuous condition must do three things:
1. Not perform ablution except after the prayer time has entered.
2. Change the bag or diaper placed to reduce the flow of urine or blood after the prayer time enters, wash the private part from blood or urine, and perform ablution immediately.
3. Perform the actions of ablution in immediate succession, then pray immediately without delay, unless he intends to pray with the congregation.
It is not permissible for a person with a continuous condition to combine two obligatory prayers with one ablution, as he must perform ablution for each obligatory prayer, even if making it up (qada'). And Allah the Almighty knows best.
Is performing Umrah an obligation for who is capable. Is he accountable for not performing it in this case?
Umrah is an obligation once in a lifetime for every Muslim. When physical and financial ability is present, it is preferable to perform Umrah, as well as Hajj. If one can afford to perform Umrah but not Hajj, then they should begin with Umrah, especially since Hajj nowadays is not accessible to everyone who wishes to perform it. In contrast, Umrah is more open and easier to undertake. And Allah knows best.
What is the ruling on someone who perform their prayer after finishing it because they believe they missed a Rak'a, a prostration, or that they did not perform it correctly (thinking their prayer was invalid)?
If he was sure that his prayer is void then reperforming it is an obligation along with figuring out the reason of invalidity so long as this wasn't out of uncertainty. And Allah Knows Best.
What is the torment of the grave?
We seek refuge in Allah from the torment of the grave. The important point is that the cause of the torment of the grave is disbelief or committing sins without repentance. It affects the soul, and the body is impacted by it, even if we do not see it. And Allah Knows Best.