Najafi Q&A: The will

Is it permissible to give the deceased an embalming injection if they requested it in their will—for example, for transporting them from abroad to their homeland or from their hometown to Najaf al-Ashraf—because, without the embalming injection, their body cannot endure the journey?

If the deceased person left a will that the remaining one-third of his wealth should be spent on charitable causes, and his wife is poor or some of his children are poor, is it permissible to spend some of the one-third on them, and would it still be considered charity?

What is Islam's view on wills? Are they valid before death?

My grandmother passed away, and we found in her will that a mourning council should be held for her every Friday night without specifying the duration. Should this be executed? If the answer is yes, for how long should we do it?