for some locations and treatment providers yes this is perfectly fine and for others it isnt...

for example there have been times when in therapy my treatment provider and I discussed meal planning and that at that moment doing self injury and other negative behaviors were at its highest right before bed. my treatment provider did text me what he had for dinner, because I had asked him to during our session and gave me a good night text because I asked him to during our sessions.

my wife too was a bit un. nerved by this because she was not in my therapy session so did not understand what context this was being done. she didnt think we were having an affair or anything like that because she knew my sexual orientation was same sex / lesbian, but it still bothered her because she didnt know the context in how this came about. my wife trusted me so she mentioned her fears then let it drop because she trusted me.

basically having a spouse in therapy it takes trusting the loved one is doing whats best and if they feel its not an ethical relationship then its their job to say hey I dont want you sending me texts any more after hours.

line in the sand is that this is his therapy relationship with his therapist so he is the only one that can say whether this is ethical or not based on what ...he....is going through. it would be different if you were also part of his therapy sessions and he gave you permission to question his and his therapists relationship but there is a way if you choose to proceed with this for your own fears and such...

to find out if this is ok in your own location and based on your own locations ethics laws you would need to contact the mental health agency that over sees your locations treatment providers, licensing and such.