i have my apple watch 6 and sent it to the philippines can my kid still use it in the philippines

NOTE: the Philippines are not currently listed as having a carrier that supports the Apple Watch.

https://www.apple.com/watch/cellular

So no matter where you got your Apple Watch, your kid could ONLY use it as if it was a GPS only Apple Watch. That is to say, if the Apple Watch has a cellular radio, there is no Philippines cellular carrier that will talk to it, so the Apple Watch would just behave as if it was a GPS only Apple Watch.

NOTE: The GPS only Apple Watch can do Everything the Cellular model can do AS LONG AS your iPhone is nearby, where nearby is generally somewhere in the same moderately sized home. The Cellular model allows you to leave your iPhone at home while you go for a walk, run, bike ride.

A GPS only Apple Watch can be used with any iPhone 6s or newer running iOS 14.

Cellular Apple Watches have radio chip restrictions:

There are 2 Apple Watch cellular radios

• Canada, U.S. Mexico, Puerto Rico

• The rest of the world

Carriers will not attempt to connect to an Apple Watch that does not use the correct radio.

If you do not get your Apple Watch in your own country, you may have to return the Apple Watch to the country where purchased to get warranty service.

If you do not get your Apple Watch in your own country, there may be country specific restrictions in the installed Apple Watch software that prevent features from working when you get home.

https://www.apple.com/watchos/feature-availability