Ask HN: is it ok to accept an offer without knowing your equity?

A friend of mine recently received an offer from a series c healthcare company with ~$100m in funding. Seems the company is in the midst of raising a series d and so as a result can't (or is unwilling) to disclose the exact number of options he will be granted, nor the pricing etc. The prospective employer said that the detailed info on number of options will be disclosed in Q3 this year after the round closes. That said, there is clear mention of a stock plan in the offer letter (4-year vesting schedule, etc.) - he's just missing the exact number of shares, pricing, etc.

Is this ever a standard practice? Is this something he should be concerned about? Thoughts and suggestions greatly appreciated.