What advice can i give to my mom...?

Hello, my mom(45yo) and dad(48yo) had a fight last monday. It was all bec of the msg that she had read on my dads cellphone. The msg was from a woman telling about if how much she cost for a night or something like that. This is not only the first time that they have fought about my dads text mates. My mom burst out with anger and now she asks me for an advice what to do. She doesn't want dad to go home anymore, to live with us and as of the moment i can see that she doesn't want to make up w/d dad. Im worried about my mom esp her health now that she's in her menopausal stage. As an open minded person i also understand my dad and being the eldest from the siblings, mom always talk to me about anything and everything and i dont know what to advice but to get calm and not to make any resentment towards my father. We are also living in a country with no divorce. Im confused of what to do now, what if both of them will ask for an advice, please can anyone shed some light for me. Thanks!