Terrific, his brain is getting more and more stimulated, and I hope he is enjoying it because it is something to be pleased about, the brain needs those reward signals just like a pet responds to treats. I think this is fabulous progress.
Slow and steady wins the race. That’s great news. New neurones in his brain are triggering and making connections again. It will happen with patience and time. This is a definite positive to be proud of. Long may this improvement continue
I echo all that has been said and wish you and your husband continued success.
I like the fact that he practices when you are out - this suggests strength of character and various other positive vibes for which right now I am struggling to come up with correct descriptors, but I feel sure you know what I am takking about.
When a milestone has been reached like this, I think you should celebrate it or enjoy the moment with your husband (and family if you have children - sorry I can’t remember if you have mentioned this). Celebrating in this way is a booster and it helps prepare for the next milestone.
As @jenny-wren suggests, a diary would be a great way to record the milestones and you can look back on how you have progressed over time.
Also, when you get [minor] setbacks or reach plateaus you can review the journey and remind yourselves how well you have done.