SD, i just checked with a colleague who's son caught the HFMD a month back. he say fully eruption of the virus will be on the 5th day and it takes a week n a half to recover.
he suggest apply bonjela n watermelon powder to ease the pain n discomfort in the mouth. use either OralB or Listerin to gargle mouth (make sure Ash dont swollow it!). But Listerin may be too "hot" n will sting n cause the mouth alot of pain, try OralB if Ash cannot take it. Make sure she washes her hands frequently. And of course home must wipe n clean more frequent.
When the virus is at its peak, his son could not sleep, so perhaps you have to anticipate that too.
As for food, no hot or warm food, have to leave the food to cool off then feed. Drinks will be anything ice cold or cold or cooled off will be good.
but then he say hot or warm drinks n food in a way is good too as it sort of burnt off some of the infection (??? think think like logical but think again like very funny thinking haha)
Lastly, his son's pediatrician told him to bring his son outdoor more often, to the beach, park, playground. Expose him to alot of bacteria so that body can accommodate it. He told me the 2nd time his son's friend caught the HFMD, his son is ok. Try it.