My brother and I inherited a brokerage account from our father divided equally. We didn't take ownership of the account for 3 months after his passing. A 1099-DIV was sent in Dad's name for dividends accrued during that 3 months. The brokerage house won't issue new separate 1099's. How do my brother and I handle this on taxes to divide the responsibility of the dividend gain?
It depends on how the will was worded and at what date the account passed to you and your brothers.
Was there an Estate set up?
Normally that dividend income would have been included on the estate's tax return. When a person passes, a final 1040 will be filed which includes income up to the date of death. After that time period, any income earned from assets owned by the estate of the deceased which generate income, must be reported on a estate tax return, form 1041.
However, if the account passed to you and your brother at your father's death, you would have to include the income on your own tax returns.
So you will need to look at the will and determine ownership of the brokerage account during that time period.