... that doesn't fit "If it would help", because that would read as "If it were willing to help, then ..."
You are right. I was making a general point, and did not notice that it was not relevant to saloom's example.
I was thinking of such examples as:
I would be grateful if you would drive me to the airport tomorrow.
Of course, "were willing" fits the second "would" in the OP's example.
I don't think it works there, either. That's just the normal past-tense form of WILL in a second condition.
I can't actually think of a convincing explanation for the first 'would' at the moment. Clearly we have a more hypothetical version of 'If it will help, I will be grateful to discuss this with you', but we are still left with the question of why the first WILL is acceptable.
The only thing I can think of is an echoing of an unspoken idea. In the first dialogue below there is an explicit statement that is echoed in the
if- clause; in the second there may be an unspoken condition that is echoed in the
if- clause. :
A: Emma will be here tomorrow.
B: Great! If Emma will be here, I'll be able to ask her about the Morton contract.
A: (It will help if I tell Luke about it.) If it will help, I will tell Luke all about it.
Incidentally, I don't find 'I will/would be grateful to discuss ...' very natural. I think we can be happy to discuss something, but grateful for the opportunity to discuss something.