Hi There is lot of bone loss for direct implant placement as I believe is already mentioned to u by the Dr. So only after a bone graft an implant is possible. Your medical condition should be good enough for implant. Should not be diabetic especially, as there are chances of failure in uncontrolled diabetics. 2. As the adjacent both teeth seem to be carious. The back tooth will need an rct and a crown too. So u can go for a bridge, if you do not want much invasive treatment. Both the treatment options have there pros and cons. As the adjacent teeth are cariously involved bridge can be a good option too, but it will not prevent your bone resorption in the extracted site.