An elderly person who has to say kaddish but is unable to stand — may he in his situation sit down and say kaddish? If yes, what is the makor for this?
Although one should say kaddish standing, where this is very difficult it can be said sitting.
There is no explicit source that obligates saying kaddish while standing. However, we find that even those who hear kaddish have to stand (at the very least if they were already standing before; see Shulchan Aruch 56:1 and commentaries), and of course this will apply even to the person saying kaddish. However, there is no prohibition of saying kaddish while sitting, and therefore when difficulty is involved it is permitted to do so..