Skynight, that is great! It seems that G realised the situation and decided to own up and make things better, which is definitely very good of him! Getting off to a bad start happens but I do believe things can get better, especially with the therapy and the new policy of talking together more.
I think spending time together, the three of you, should help G feel less like an outsider, although of course it will probably take some time for you guys to get into the new dynamics of things.
Of course, you also need some time in pairs... Including you and G so you can get to know each other better and bond.
I think it took a great turn and I hope you'll manage to stay on that road. It seems G wants things to be fair for everyone, too, so that's good.