I have a guest who wants to stay for 34 days. He is asking if the payment can be split so he’s not paying for the entire thing at booking? I’m totally fine with this but I cannot find a way to do this on my hosting end. Everything I see says the stay has to be less than 28 days. It sounds like he will he charged the first month right away and the additional 4 days later, but I’d like to split it into two equal, or close to equal, charges to help him out. Is there a way to do this?
No, you can't do that.
And it's a really bad idea anyway. What happens if he never makes the next payment and he's already in residence? Airbnb would send you a message saying "Oh, sorry, we couldn't collect the payment" and you'd be left having to try to evict him.
A guest who can't manage to come up with a month's rent at once isn't someone I'd want to be hosting. A guest's financial situation isn't your affair.
And in most places, someone who stays a month or more falls under landlord/tenant laws and could be almost impossible to evict in a timely manner. You could be stuck with a squatter for months.