Should my elderly mom skip senior classes whenever it rains?

My sister says if it rains my mom should not go out due to the possibility of her getting sick with flu and we have to take care well of her. My momis an elderly woman and yes I do agree that we have to take care of her cause if she gets sick with a fly or cold it can worsen and we dont want that of course. But there is something I disagree with her. My mom to be active and distracted she receives classesat some senior center in a city like 20 minutes from home. Her classes some are in the morning and some in the afternoon. Since I live in a country where the rainy season is heavy, soon we are approaching that season where it can rain mostly in the afternoon.

Unfortunately some of my mom classes are in the afternoon and it be a sure thing that whilewe are in the rainy season there is a high chance it is going to rain in the afternoon, something I dont have control of. Still with rain people will go to classes and carry umbrellas, raincoats, sweaters, etc. My mom is one of the few elder people at center (due to her age) most of the students there even if they are seniors they are not as old as my mom.

My mom can walk but she walks slowly with the help of a cane. So in a case of rain i mean even if she will be cover3ed in coats and umbrella, she may still get wet to get inside my brothers car when we pick her up after classes this is because the institute entrance is not covered for the rain it is in the open.

Anyway my sister had said that if it rains my mom should not attend classes at all, she should stay home, she is very afraid that even the harmless flu can be bad for mom and she may die for pneumonia (she is vaccinated for pneumonia and flu anyway even Covid) But then I think, but what if all the bimester it will rain all the days my mom goes to classes in the afternoon or maybe even in the morning?

Updates
2 mo
Does it mean that my mom can't enroll classes just for the rain and stay home the whole time? I mean going to classes distracts her from home so she can do something different than being stuck at home and just watch TV in bed.
Should my elderly mom skip senior classes whenever it rains?
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