Sciencephd, thanks for your reply.
Maybe I should ask him when he will get the funding.
I have sent about 40 application mails to research groups all over the world, now I had better continue searching.
No, it's not an offer. He doesn't have funding for a position, therefore he can't make an offer, so I wouldn't make too much of it.
But you need to ask him what he means.
There is no way that he will know when he'd have funding.
It means he doesn't currently have any money in his grant budget, and writing new grants and waiting for funds typically takes about a year IF he is successful... so you could be waiting for a very long time. There is no offer here, just a hint of encouragement.