Baby diarrhoea

Hi all, my 5M old LO has diarrhoea for 6 days already. He was on mixed feed (70% BM). Went to see PD and was prescribed Vivomixx probiotics. Was advised to give fully BM or change to other FM (gentlelease etc) and monitor for another week as it will slowly recover. We decided to go fully BM on 4th day but LO is still pooping frequently although he is feeding well and active. My question is whether any mummies continued fully BM and how long does it take to recover? Appreciate any advice. Thanks.