After my grandpas death a few weeks ago, my grandma has gotten very pale and weak. i was watching her walk and noticed that she stumbles a little.

Take her to see doc: I'm sorry to hear about your grandfather's passing. Your grandmother may be suffering from grief at his death, possibly even depression, as she may be pale & weak from not eating (total conjecture on my part) or some other reason. However, i'm concerned that you've noticed her stumbling. That isn't normal and needs to be evaluated by her doctor as soon as possible. At the very least, go to pt.