Would you skip these things in order to avoid getting sick?

Emma

My sister’s baby was sick with a 104 degree fever on Sunday, and her husband was in the ER with a stomach virus on Monday night until Tuesday. My brother was babysitting her daughter on Monday and Tuesday. I’m a stay at home mom so if I get sick my husband would have to take off work or I’d just have to deal with it and I really don’t want to deal with all that, so I don’t want to get sick. My sister just sends her baby to daycare sick or not so she doesn’t care. Literally every time we spend time with her family, we end up sick. I’m wondering if it would be a bad idea to go to these things-

1- my brother wants to come over today and spend time with my toddler and I. Could he be contagious?

2- breakfast with my brother and dad (who lives with my brother) tomorrow at a restaurant

3- my sister’s throwing a birthday party for her daughter on Saturday. Could her or her family still be contagious?