Just so you know, that's a really common scenario for tics to come out in an explosion at home after school. It's a safe environment plus even children as young as your nephew will suppress tics in the presence of strangers, or their peers or even in the doctor's office. A tic is a little like a sneeze, it builts up tension and if you hold that sneeze in and in and in and in and in and it builds up... in the end comes a really big explosion of a sneeze.

Tics can occur in a number of conditions. My opinion differs from some, but I suggest that his parents and everyone just absolutely and totally ignore the tics. If they continue, then there are some things that can make it easier to sustain a day in a classroom, like taking short breaks, having some energetic exercize time to enable the child to "let them out" etc.. that way supressing them doesn't leave the child in a state of exhaustion or distraction when they're trying to learn. If the weather is good/ or when it does get good, spending some time out in the yard or on a trampoline or swings or something like that is an excellent way of allowing a child some space and during the period of physical movement the child can actually let out some tics if they need to without feeing under scrutiny.

The almost perfect scenario for my son years ago in school would have been for everyone to just ignore his tics and he'd have not spent all day suppressing them to the point of exhaustion but life isn't like that unfortunately.

Actually quite a significent number of young children between the ages of about 3 and 7 get transient tics, which remit on their own very quickly. It's much more common than people think. As I said earlier, tics can occur in a number of conditions. Not all that tics is connected to Tourette Syndrome or PANDAS I mean. Even with Tourette syndrome, and I'm not saying your nephew has Tourette Syndrome at all, but the prognosis and chance of a child growing out of their multiple tics is very good indeed.

Some children on autism spectrum also have some tics, motor or vocal/phonic or both... plus children on autism spectrum can have stereotypies.

The number one thing I would consider at this point is that your nephew knows that he's going to be OK. Little children hide a lot of fears in their heads, especially clever little heads that might not be as communicative as others. Sometimes children can become frightened when they're being scrutinized for tics or behaviours that are different from the expected and especially so like my son who was having to have lots of tests and proceedures that were invasive, like all the blood tests, and MRI's etc..

That's actually one part of the whole process to diagnoses that I wish I could change a LOT because it was all pretty frightening to my son as well as me, thinking there was something really seriously "wrong" with him. If I'd known then what I know now, I'd have approached a lot of things very differently. Sometimes though one has to explore with certain proceedures to eliminate certain serious illnesses or conditions which might have similar symptoms. When that does happen, it's just so important for a child to be aware of what's happening (age appropriately) and get lots and lots of love and reassurance.

all the best.
Lara