Where do I stand with regards to jointly owned home?

With your brother being half owner of the house you are in a difficult situation. You might need to think of something somewhat dastardly to force the issue. There are numerous possibilities for dastardly strategies but here's something that might get you thinking outside the box. Since you are half owner of the house you have every right to make upgrades and repairs. Perhaps you decide to upgrade the plumbing and install a new energy efficient water heater. In order to do this you must shut off the water at the main and remove the water heater. After removing the water heater from the property you discover that you must use your disposable capital on an emergency issue. This delays restoration of water service to the house indefinitely. Perhaps at that time it would be best if your brother found different accommodations and then you list and sell the house. You can see that the scenarios for this type of underhanded tactic are endless. Just remember that your brother is treating you underhandedly at this point so maybe outwitting him this way is justifiable.