I have vowed that if Allah gave me what I wanted so bad, I would fast every Monday and Thursday to the rest of my life; unless there is a valid excuse hindering me from doing so. Fortunately, Allah gave me what I wanted, so I started fasting Mondays and Thursdays; however, I stopped out of laziness. What is the Sharia ruling on this?
All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Allah The Almighty described the righteous people of Jannah where He Said (What means): "They perform (their) vows, and they fear a Day whose evil flies far and wide." [Al-Insan/7]. Accordingly, you must do your best to fulfill your vow. However, if you are unable to do so, then feed a poor person for every missed day of fast (About half a JD), and if you are unable to do that, then offer expiation for breaking a vow, which is feeding ten poor Muslims (About half a JD for each), ask Allah for forgiveness and increase remembrance of Him. 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.
Is prayer mandatory on a dying person who goes through a state of unconsciousness, then wakes up?
If he wakes up and was conscious, then he should pray the way/manner he could, but if he wasn't, then he is exempted from obligatory prayer as Allah Says in this regard (What means): "On no soul doth God Place a burden greater than it can bear." [Al-Baqarah/286].
Is it permissible to offer prayer at home, or should it be offered in the mosque?
All perfect praise be to Allah, The Lord of The Worlds. It isn`t preferable for the man to pray at home as praying in the mosque is twenty seven times more rewarding. Therefore, this should motivate him to offer prayers in the mosque. And Allah Knows Best.