1. A Joint-Ownership property owned by Two persons, CANNOT be sold (in any manner, whatsoever), UNLESS & UNTIL proper legal "partition proceedings" is conducted, through a court of law.
2. In instant matter, since the property is a residential Flat, IT CANNOT be partitioned and neither the other brother can evict you EVER, in any manner, whatsoever.
3. You have to conduct legal proceedings to Transfer 50% Title-Ownership of your Husband, in your name /your childrens name, for your futuristic financial & social security.
4. Also kindly prefer to visit the following link, for some basic introspection:
Keep Smiling .... Hemant Agarwal