SOLVED. about boy who discovers world he is from, grandfather helps, something about a key. [s]

[Halah]

I read a book a few years ago, all I can remember is that its about a boy
who cant remember anything before he was 7 and he is told because he was in
a car accident that killed his parents. He lives with his grandfather who
is considered crazy, drawing with chalk all over the street. Later realize
that this was done for a reason. They have a care taker, an old woman who
is mean and hates them. The boy likes to draw and usually draw unusaul
things like mythical stuff and knows somehow it is related to past. The
grandfather is usually in the attic and the boy can hear him talking to
himself. On the boys birthday, grandfather gives him a pencil and when the
boy draws with it, he draws a key I think and it becomes real. Um, the
grandfather dissapears or something, boy is sent to a boarding school by
the old lady who seems to have a relationship with the headmaster. A
package arrives for boy and it is from his grandfather, it is a mirror. He's
confused. Stuff happens, somehow he comes into this diff world, a girl
follows him. ER, something about finding candy in the middle of woods, then
they are rescued by old man who they find out is the grandfather. Boy realizes
he is from this world and that he wants to save his mother. I cant remember
anything else, he fights a dragon, finds out he has a brother, something to
do with keys... (view spoiler)[ The headmaster is the evil villian along with the care
taker who is killed by the headmaster in a cave when they are stuck in it. (hide spoiler)]
Something to do with vines...The cover of the book had a key on it coverd in vinesI
think..
Please help I've been looking for this for ages! Thanks.

[Ann aka Iftcan]

How long ago was "a few years" Hallee? And did it feel like a new or old book then? And is it YA or adult?

[Halah]

Three years ago, it was new, and in the tween/children's section of the library. It had maybe over 200 pages. I remember that the author was going to make a sequel.
The cover was black with an old fashioned key in it, covered in vines I think.

[Tab]

Smudge's Mark sounds like the book

[Halah]

Tab wrote: " Smudge's Mark sounds like the book"

Yes, I think that's it! Thank you!!