Linking accounts

Hi

(This is the first of 2 questions, posted separately as they are different topics)

I saw from a recent question that multiple children can be added to an account. My needs are slightly different. I work with a charity supporting children with a chronic medical condition.
I would like to be able to create an account for each child with some details of the condition and then create separate accounts for each of the parents/carers. The parent/carer accounts would then need to link to the childs account in some way so that we can access that information, e.g. when the parent registers for an event.
If that isn’t possible then maybe a simple link field so that we have some way of matching users?

Many thanks