If you purchased the insurance, and you listed your brother as a dependent, you are the only one who will get a 1095-A.
You are dividing the cost of the insurance with someone not on your tax return (TurboTax will ask you about that when you enter the 1095-A). You both need to report the information, since he is not your dependent.
You and he need to have a conversation about how the amounts listed on the 1095-A will be divided. You can assign any percentage of the costs you choose - anywhere from 50:50 to 100:0. He will need a copy of the 1095-A, unless his income is less than the filing requirement ($10,350, or $400 in self-employment income), in which case he will not need to file a tax return.
If you assign yourself 100% of the amounts on the 1095-A, then you will get the refund if you have paid too much for the insurance; if you have paid too little, then you will owe the difference. With any other percentage, those amounts will be shared.
To enter all this in TurboTax, see TaxGuyBill's answer below.
https://ttlc.intuit.com/replies/4909853
