i feel bad for my fish

so i have a betta fish that is like, really sick, but the medicine wont work 
he has like a fungus ball the size of a mechanical pencil eraser on his back fin ;-;
which doesnt really sound bad but he is really tiny. sometimes he sits there and its just.. ugh
its really sad because he has to keep flapping one of his fins to tell us "hey im still alive dont flush me" and that is just sad
theres also a little algae on his tank so he sits where it grows most and just drifts around like "this is it. death is coming. i welcome it." then he like wriggles like "no wait gotta get comfy" and continues drifting and if that isnt extremely pitiable then i dont know what is