My friend is semi-paralysed, my other friend isn't aware enough and always asks her to do things she can't do?

Yes! You should tell the other person! They might think you are mean, but you are helping t preserve the well-being of another friend in phisical need! If you see the other friend asking the paralyzed friend to do those things after you tell them to not, then cntinue to remind them. The paralyzed riend could get seriously injured!