

Tell the truth, and quote the customer without that feature. Make it clear that that feature doesn’t exist, and your company can’t make it, and your supplier isn’t interested in working on it.
Your boss had time to sort this out, and failed. He asked you to move forward as if it was solved, which means lying. Instead, tell the truth.
You could run it by your boss before sending it to the customer, but don’t let him insert any bad-faith statements if you’re the one signing the quote.
We did, imperfectly. Stomach acid is one example – it kills enough pathogens that people who take medications to reduce their stomach acid are actually at higher risk of foodborn illness.
https://today.ucsd.edu/story/common_acid_reflux_medications_promote_chronic_liver_disease