Anything wrong of me for telling this to my child?

Hi I have a 70yo plus father in law who is still a smoker, drinker, gambler and a womaniser who often sleeps with indecent china women until now. Anyway this is him and he has been doing all these with or without my late mum-in-law. When my mum-in-law is around, she never even allow my father in law to put & mix his clothes with rest of the others into the washer for washing, her main reason was worrying if he carries any STDs (e.g: Herpes) and may infect the other family members. Even his own children (my hubby & his both sisters) despised on him and also think he doesn’t deserve to be respected at all. So I have a young toddler whom I often told her not to stay too close to her grandpa (referring to my father in law) when she’s very young, I emphasised many times to her don’t allow him kiss and touch her all the times. Now my child is old enough to express herself so she will say in front of him during our family gatherings or even when doing video recordings too. I did feel abit embarrassed for this when they learnt about why my child is saying “grandpa is dirty!” but at the same time, I don’t want to deny how this is what I felt and wanted my child to stay away from him (worried he has any sexual diseases etc). And I feel so upset because my sis in law once told my husband to tell me to try leave a good impression of their dad to my child, but how to accept this and lie to my child about my father in law is actually a good grandpa? In fact, he is not a good grandpa at all, he seldom visit my child and has never bought much things for my kid if he really dears her, he squandered all his money on gambling, drinking and patronising women. Instead for my own mum, I have never ask her to do all these but she will purposely travel all the way via mrt, buys food, toys & even concocted herbal soup for my child (her grandchild). What would you do or say to your child as a mum if you were me? Did anyone of have experienced the similar father-in-law like that? Are you not concern if your dad-in-law (with such vices) will affect my child, especially the STD part including Herpes)?? Thanks for good advices.