Thanks for asking. I gone through your question and understand your concern. you said that your friends daughter has been diagnosed with hand foot and mouth disease. you said that she played with your daughter 5 days before, I want to a mention point here that, duration(incubation period) between the virus that goes to body and the illness like fever is generally 3 to 6 days in hand foot mouth disease. so as you said that 5 days has passed since she not developed and symptoms. it is very unlikely that she will develop the s disease now. yeah this is you can spray her toys with lysol to prevent infection but after spray with lysol wash with tap water before your kid touch them. thanks hope I answered your question.