Dr. Supriya Wakchaure- Pediatrician and Neonatologist.

Maybe your child is not able to hear as well because the outer hair cells in the cochlea are affected. Not only this but the child may lack in hearing or have difficulty in responding to the everyday sounds as it was before. This disorder can be due to infections or because of exposure to loud noises. The positive side is that an audiologist will be able to diagnose the issue and provide solutions, such as hearing aids. 

Rheumatoid arthritis does not harm your baby through breast milk. It's a kind of autoimmune disease that has joint pain and swelling issues. You are not giving your baby the disease through breastfeeding. Following your care regime as your doctor indicated is essential. Only if otherwise told by the doctor of medications that are not suitable to take during breastfeeding.

Sometimes having enlarged adenoids can make them more susceptible to cold. Perhaps swimming is a factor that irritates his adenoids. It is important to ensure his health is not sacrificed for his swimming hobby. I suggest giving a short break to him swimming and observing whether his adenoids get better. This might help him get less affected by cold.