I hope they both get better soon.
Both kids and I have had it.
My wife has never tested positive and according to all the massive bloodwork they did when she almost died a while back, she has no antibodies for any of the strains, so she has never had it, even though she lives with three other people who have had it.
My daughter had one strain and my son had another. I'm the only one of us who has had two strains of Covid19.
Now there's a third identifiable strain, I understand.
Knocking on wood here, but none of us have gotten sick.
Hope your parents come out of it just fine!
(all that about us is supposed to encourage you!)