There are some real positives in your post & you should both take these as encouragment that the brain is working to re-establish the signals.. it will take work but there is every reason to believe that.mire progress can be made.
I regained the use of my arm by exercising it daily. My leg is still a work in progress byt there are others who have regained use of both.
It is encouraging that he managed to eat some custard. @Mich-mm has recently started eating some food after being on a peg. See post below.
Best wishes
Ann