Whenever I read something like this I am relieved to have skipped calculus :))
Ahah :) In fact calculations look scary, but they are doable with time. The main problem is that reaching the exact cancellation of all infinities (a necessary thing) is often extremely hard. Any stupid mistake propagates all over the place. This is however something necessary for precision predictions, which we need.
I am very happy your wife has recovered nicely. Even though she is relatively young and healthy...still things go wrong sometimes and it's nice things went well for her. It is sad for your son. Particularly if he is feeling fine, he will be restless. Still...he is feeling well, and for that we can be grateful. Stay well, @lemouth. Whatever your secret, I'm happy COVID avoids you ;))
Today, everyone is negative again, and I managed to escape it (for now). The trip to Boston in 12 days is still confirmed :)