What to do with the worries we can't do anything about

I know there are many people with worries at the moment.  Our son Anthony is autistic and has ADHD and struggles with lots of things.  He suffers from anxiety.  I have my own difficulties in 'letting things go'.  It leads to further issues with sleep in our home and can have a general affect on how the boys cope daily.  They have less resilience and this puts us at greater risk of mental health issues, especially now.