NI credits and PIP

This is a bit complicated! on behalf of husband who was recently awarded PIP for 10 years. He got ill health retirement 3 years ago . His state pension forecast was for a full pension at that time .so he didn't apply for ESA for credits only , as we knew he wouldn't get it as his work pension was good .. Under the new rules for state pension, his NI record is short and we have been going round in circles between pensions and NI depts. to try to clarify whether he can get credits now until; he gets his state pension in 2 years. Time . Is there any provision as a PIP recipient for NI credits?
( we know he can buy conts. . but obviously we'd rather avoid this.)
This issue of 'missing years' is a bit of a shocker as we thought we'd done the right thing in getting a forecast when he had to give up work. Other people may be interested in this as it does seem to affect people who are retiring soon and caught between 2 different sets of rules for State pension . Anyway , thanks for reading and as always, thanks for the wonderful advice and sup[port you always provide.

I'm afraid there are no NI credits with PIP as this is not a wage-replacement benefit.