How many I-134s when the co-sponsor is a couple?

[Jersey Girl 2]

Sorry if this has been asked a thousand times before, but. My brother will be a K-3 co-sponsor. His income tax filing status is Married Filing Jointly. He and his wife have assets together and there are some they hold separately.

Do they fill out one I-134 and add a sheet of paper to list all assets? Or do they each have to fill out a form? (The wife's salary is below poverty line and she would not, on her own, qualify as a co-sponsor.)

[YuAndDan 153]

Remember you only need to start start listing assents when income is less than 125% poverty line.

Questions:

1) What is your income? If below poverty line then consider your liquid assets.

2) Your income and (assets /3) still below 125%? then get a co-sponsor.

Your co-sponsor only needs to promise to make up the difference between your income+(assets/3) and the 125% poverty line.

So brother most likely needs only to list his personal income on the I-134.

I hope that makes sense.

[Jersey Girl 2]

I've decided to have a co-sponsor to be on the safe side, so let's leave that aside. My question is: how many I-134s are needed? It's prompted by this sentence "If the sponsor is married, the affidavit should be signed jointly by both husband and wife." It appears in a Captain Ewok post I-134 brief details of requirements

Common sense says one form, filed out by the brother (who is the co-sponsor), but signed by both. But I could be wrong. The next question is: if it's signed by both husband and wife, do they each have to swear before a notary?