Hi,
It looks like the child has very weak immunity and hence the stated issues. Given the situation, it would make sense to ensure the child eats well to build immunity. If not, there is a good chance of the niggling issues turning chronic (easy for me to state. But then, it does look like the child will continue to have have issues).
If I were to take the liberty, I’d encourage you to consider following the guidance provided by respected TKC.
Take care…