Who is “the poor” that is entitled to receive Zakah(obligatory charity)?

The poor is the one who has neither money nor a source of living, or has either of them, but it isn`t sufficient such as being in need for a hundred JDs, and having an income of forty JDs only.

Who is required to fast?

Any adult, sane, and hardship enduring Muslim person is required to fast unless there were prohibiting conditions such as menstruation and confinement.

What is the ruling on a woman shaking hands with the brothers of her husband`s father, and not putting on Islamic wear before them?

The aforesaid are strangers to the their brother`s son`s wife, therefore, it is forbidden for her to take off her Islamic wear before them, or to shake hands with them.

I am a disabled woman who has vaginal discharges and can`t control her urine. Therefore, I combine prayers. Is that permissible?

All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all his family and companions.

According to the Hanbali doctrine, it is permissible for the sick to combine prayers. In your case (Asker), it is better that you delay the noon prayer until a few minutes before the afternoon prayer in order to minimize the time span between the two and perform each alone. In addition, you can do the same with sunset and evening prayers. Finally, we ask Allah to bless you with recovery. And Allah Knows Best.