Tenant screening, son over 18

[Steve C.]

Hello all & thanks for reading. Apologies for not being on the forums for a while, I felt I'd learned all I needed to get started & now I'm screening tenants for my first rental property! I have a SFR for rent, i'm using the application from Brandon Turner's book on managing rental properties & the qualifications listed there in. I have a tenant with a 610 FICO, a recent BK from a divorce (so no debt going out each month), however he has a son over 18 who is splitting time between him and mom.

My question is, what do I do with the adult son? Background/credit? Co-sign the lease? Nothing if listed as a dependent on tax returns (did some searching on the forums already).  A little background on the tenant, he lives in the area in a rental with some serious plumbing issues & has said they're willing to let him out a month prior to lease end due to circumstances, or if they won't honor that statement, he's willing to leave early & double pay rent that month to not loose our listing. No evictions or late payments, 30k in the bank from sale of prior home, social security of rent due each month & still working bringing in 3x rent each month. I like not paying holding costs by getting it filled, but don't want to get into a situation if son may be a problem. What would you do/have you done in a similar situation?