I don't think it's an excuse.
But the fact is, that R has a "cost" associated with the process which may be causing a "priority call" in his mind.
R is work. It requires attention and time.
There may be straight monetary cost as well, if you are using counselors or therapists.
Even though your half-year buffer may be in place, it may define "failure" if you use it, in his mind.
My advice is this. Do not base your perception of his remorse on this. I assume that he is going to IC at a "standard" rate, like once per week, etc, a rate that would not be different were he employed?
Ask him why he feels it necessary to postpone the MC.
He is not looking for a job 24/7.
I also think you should tell him how you feel, that you think the rate at which he is pursuing his recovery should not be less than it would be if he were employed.
That he should accept that his job is now "looking for a job", devote the normal working hours to that, and handle the R just as he would if he were working at the job.