Posting this as an OCD sufferer, whose condition also worsened after having a child.
When you say that your DH is having counselling, do you actually mean counselling or CBT with a psychotherapist?
It makes a big difference - I had counselling when I was pregnant with DD and it was about as useful as an ashtray on a motorbike. OCD is generally characterised by the sufferer thinking too much, which is why many talking therapies are not recommended in the treatment of OCD
The treatment recommended in the NICE Guidelines for OCD is CBT (Cognitive Behavioural Therapy). This is most effective when combined with the right medication. I'm sure I've seen it said before that the NICE guidelines can be taken to show your GP if they are not supportive of this.
It is important to get a CBT therapist with experience of dealing with OCD, as the treatment of OCD is very specific, involving ERP Therapy (exposure and response prevention therapy) - which is very scary, but ultimately the most effective therapy for OCD sufferers, where the sufferer has to do practical exposure "experiments" where they face their fears and ride out their anxiety.
I recommend ocd action. There's also an organisation called OCD UK. Both of these organisations offer information and support for both sufferers and the loved ones of sufferers. Pretty sure you can get a link to the NICE guidelines from at least one of these websites.
Also, a useful book is Overcoming Obsessive Compulsive Disorder by David Veale and Rob Willson
I'm a lot better than I was (due to a combination of meds and therapy), but when my OCD has been really bad, I have been totally blinded by terror, struggling to get out of bed in the morning, and seeing everything around me as things that will cause deadly peril to my child, so it's not an easy condition to face up to. Your DH will need to make the commitment to himself and your family and be willing to put himself through some pretty scary stuff - but it is worth doing.
My marriage has not done well through my illness, so I urge you to seek support for yourself as well as DH so you can both gain an understanding of what OCD is about and how best to deal with it.
Good luck :)