If they fall sick, they will do something to cure the illness,
so they will recover quickly and able to guide the sentient
beings.
Yes, as what AEN said, they don't need to endure the pain, as they
don't suffer from physical pain.
When people mistreated you and making you angry, you must know that
it is due to their greed, hatred and ignorance they made this
mistake. It is not their nature to want to harm you. In fact, if
they remember that they were your parents in the past, they'd
rather take the pain themselves than to touch you.
In fact, most of them suffer before you, till they can't endure
it.
What do they get when they mistreat you? they get bad karma, but in
return, your bad karma reduce. If you don't have bad karma, no one
will be able to hurt you anyway.
Another suggestion is you can use a transformation method.
When one extremely angry, the anger is actually very powerful and
destructive, you then look into yourself, find your own faults, ask
yourself what I have done in the past that give me this bad karma,
why I am still so lazy to practice and improve myself, I must do
things wiser next time.
Another method is to visualize other people who suffer the same way
as you, feel their pain and develop compassion to them.
Which method to use, depends on individual and situation. the 2nd
one is good to wake up lazy people. The 1st one will make one more
compassion.
Other method will be to train yourself to be mindful so when the
anger about to rise, you will detect and avoid it.
or if you are compassion enough, the anger won't even rise at all,
then you can forget about all the above already.