Rsv and bronchitis

My son has been to a and e twice, the first time they diagnosed him with bronchitis and was retracting under his ribs they said it’s nothing to worry about regarding the retracting and than swabbed him then the next visit the next day due to the retracting worsening they informed me he also has rsv I expressed that I was concerned that he isn’t drinking his bottles as usual and the retracting also he was breathing heavily they expressed again the retracting isn’t an emergency to see my gp after weekend and sent us home he’s 5 months old and struggling? What can I do to help him