I think it's always like that when they try to rest, the tics are the worst. Been tired is also a trigger for tics.
It is hard to see them suffering, I'm going through the same thing.
The challenge is to find what are the triggers for your son.
Start keeping a log, write what he ate, what he did, if he was mostly indoors/outdoors, screen time, stress etc.
And keep reading.
For my son we discovered that chlorine (pools) was a big trigger as well as dopamine increased foods like bananas and corn.
Hopefully it helps, good luck!