until + future forms

[engee30]

Could you please tell me whether any of the following sentences is correct?

1) Tim's already 18 and that it's only a few months UNTIL he WILL BE LEAVING home for school.
2) Tim's already 18 and that it's only a few months UNTIL he WILL LEAVE home for school.
3) Tim's already 18 and that it's only a few months UNTIL he LEAVES home for school.

The person who posted the sentences on a Polish forum concerning issues on the English language insists that they are perfect. Well, I don't know. And besides, do the sentences make any sense?

[Casiopea]

I'm having a difficult time interpreting the sentences. The underlined portion is awkward.

1) Tim's already 18 and that it's only a few months UNTIL he WILL BE LEAVING home for school.

2) Tim's already 18 and that it's only a few months UNTIL he WILL LEAVE home for school.

3) Tim's already 18 and that it's only a few months UNTIL he LEAVES home for school.

[engee30]

Originally Posted by Casiopea

I'm having a difficult time interpreting the sentences.

So was I. The point is that I can't guess whether they represent any kind of a noun clause, or a time clause, or whatever. They seem to have really been made up just like that, without any grammatical point taken into.
Besides, what's his (Tim's) age got to do with leaving home for school in a few months? There's no way I can get it.
Thanks Casiopea.

[Casiopea]

In that case, delete relative that and 3) is the best choice grammatically. With additional context, it could also be semantically meaningful:

3) Tim's already 18 and it's only a few months UNTIL he LEAVES home for school.

Does that help?

[engee30]

Originally Posted by Casiopea

In that case, delete relative that and 3) is the best choice grammatically. With additional context, it could also be semantically meaningful:

3) Tim's already 18 and it's only a few months UNTIL he LEAVES home for school.

Does that help?

Absolutely! Strangely enough, I was beginning to think the same way!
Thank you so much.

[Casiopea]

You're most welcome.