IS for couple, one pregnant

I tend to over-think things so would appreciate advice from wiser heads.

Woman 37 weeks pregnant having difficulty getting fit notes for ESA from GP who thinks she should be over the grief of losing her baby last year. She was advised to claim IS as a couple on the basis that she is within 11 weeks of baby being due.

I get that but CPAG page 26 states that to get IS your partner must not be entitled to IRESA/IBJSA.

Partner is technically fit for work, however does not want to at this stage of the pregnancy and for 3 months after as he missed out on the short time they had with last baby.

Would his ability to work exclude them from claiming IS?

No, but she can only claim income support for them as a couple until 15 weeks after date on which pregnancy ends, unless she (or he) then satisfies some other paragraph in Schedule 1B to claim inocme support

Thanks very much, sovietleader