Can my brother sponsor my sfe application?

I’m in a crappy situation. My parents have separated and the parent im still in contact with doesnt have any documents whatsoever to provide as evidence for my application. I cant provide the required evidence for the marital evidence form because she doesnt have it. As a result Ive been given the minimum loan; better than nothing but not nearly enough to move out and go back to the same city my unis in. Im currently staying in my brothers house for the summer, this is my ‘home’ address where my mail goes, but i need to move back closer to my uni. I cant apply for parental estrangement because this all happened recently. i cant live with my parent because theyre living in a single residency. Is there anything I can do?