Yes, it's correct. Apart from the missing letter 'l' in 'would', it's fine. The grammar is perfect and the meaning is clear.
However, I'm not sure it necessarily means what you want to say. The impression I get from the Spanish sentence is that you're genuinely grateful for this person's offer of help. Is that the case? If it is, then the wording of the English doesn't reflect this idea.
When we say 'I'd be happy...' in English, we often mean 'I don't mind', in the sense of 'OK, it wouldn't inconvenience me,' and there's often a 'but' involved. For example, you might say "Well, I'd be happy for him to help me with this problem, but I'm afraid it's not possible because.....:".
If it's formal acceptance of a person's offer of help, you might be better off saying something like, 'I'd be delighted if he could help me'. Just a suggestion.