9 YEAR old has the flu!

My oldest son has like all of the symptoms of the flu and I am terrified of my 2 year old and 3 month old catching it!! We're pretty sure he caught it from my mom since he was with her yesterday and she has been super sick since this morning. His fever is 101.7 and we gave him kids Tylenol and Zarbees for his cough and stuffiness. We haven't gotten the flu shot in years bc when we did we got the flu anyway so we haven't made our youngest kids get them either. What can I do to make sure my toddler and infant don't catch it?? We gave him medicine and quarantined him to his room with hand sanitizer, a trash can, water, crackers, and hubby is going to get OJ and Ginger ale now. I'm so sad for him that he is sick so close to Christmas 😢 poor little big guy!!