Is your brother even willing to lend you money? When you borrowed from him before, it caused problems between you two. You still owe him money for the car and you don’t even have that car anymore. He might not be interested giving you money for the condo because it’s not a necessity.

Are you calculating association fee into monthly payments on a condo? If you can’t afford moving out of your moms house, it will impossible to afford mortgage and association fee. Frankly this condo will not be yours. It will belong to the bank as you’ll be paying mortgage plus youd be paying your brother for a down payment. It won’t really belong to you anyways. Not for many years.

Why not rent your own place? Why not get subsidized apartment? We are renting (we don’t feel like buying honestly even though we make good money) and it’s decorared and furnished by us exactly how we want it. So it’s very much “ours”. You don’t need to get into further debt with bank and brother to have place that looks and feels like yours.

Are you being realistic? Maybe talk to a financial planner?