I’d say understanding your financial upside is always important… it’s just likely the founder has yet to encounter many of the issues raised here. So while you can ask, the answer is going to be so speculative it may be useless.
That said, why not ask? Maybe the founder has their heart set on a IPO and is working towards that? Maybe they already agreed to a liquidation preference that adds some small risk. Just keep in mind the overwhelming risk is that your equity will like be worth zero so these details are somewhat irrelevant.