two different things
I think it is important to consider two different things about “relapse” in GBS. First, often what is meant is “relapse” in symptoms–meaning that it is harder to walk or increase in the pins and needle feelings or distribution or numbness. I think this is pretty common to worsen with “stress” from my own experience and from what I have read here from others. It is like overdoing exercising and probably for the same general reasons–that stress causes people to use their body differently–you may sit/move differently, sleep differently, but more important be tense or agitated. the tension or the finger tapping or restless pacing (or other increased nerve/muscle utilization) is like increased walking. This should be a kind of temporary thing although it is scarey, it does not necessarily mean that the immune attack is worse, just that the nerves are at that time trying to work at a different level than before and protesting or not being as effectient because of previous damage. (That is, not new damage, just uncloaking of the old damage by pushing the nerve to work harder).
The other side of this is that major stress especially if prolonged–like taking care of someone you love who is very, very ill or dying or having major surgery affects the immune system balance and can cause a relapse of the disease–meaning a new attack on the myelin and additional damage formation. this is less likely, but it is possibly what happened in the case your mom is worried about. Some people relapse and whether that person relapsed due to stress, the degree of stress they had, and all the other many factors that affect this disease, you do not know in this situation. Life is stressful–especially life with GBS and we all are stressed more than every before in ours lives, but true relapse of the disease is rare. I hope that that gives comfort to you, that the stresses really to worry about are likely the major life changing ones not the day to day ones and that the “return of symptoms” or “residuals” are not the same as new damage happening.
I do not know this for a fact, but this is my understanding of a complex problem from years of thinking about autoimmune problems in other people and for the year and a half that I have lived with this in myself.
WithHope for a cure of these diseases.