どこ literally means "Where"... So I'm not really getting the point of your question... You can, for example, ask "Where do you live?" using どこ, as in「どこに住んでいますか」 I'm not sure what are you implying by "has gone" there, is it like "going to a city" or "became dead"? Either one, どこ should be acceptable to be used, since the term itself means "Where". You just need to change the verb 明日彼はどこに行きますか --> Where will he go by tomorrow? 猫ちゃんはどこで死んじゃったのか --> Where did the cat died?

We use どこ with particles very often, like you do in English with "at, in, on, to, from, etc". We put particles just after どこ, so ee say どこに、どこへ、どこで、どこを、どこから、etc. Besides, we use どこ for "everywhere, nowhere, etc", with particles, どこでも、どこにでも、どこからでも、どこへも、どこにも、etc. So, there are many use of どこ in Japanese. I hope this wal helpful though it's only a little.

Yep, basically the same way that you use the word where in english. In addition to that, you might often here the phrase, or be asked: 日本のどこがすき？　For example。 And this phrase doesnt mean　Where/What place in japan do you like？　But it means "what do you like about Japan"