From one angle he looks very much like a dwarf lop, in the last photo he looks uncannily like a french lop I once fostered. So he could be some kind of lop cross (french lops are 5+kg and he doesn't look big enough for that), or he could just be an overweight dwarf lop, if he's had a poor diet and no exercise he might just have some chub - an average dwarf lop is usually somewhere between 2-2.5kg, or he could just be a big dwarf lop - my Harry is probably mostly dwarf lop and he's just over 3kg, so there is a lot of variance in what is "normal".
Whatever he is, he's gorgeous, beautiful colouring and probably feeling very smug with himself that life has just got a lot better for him!