Hi RB1975
Your partner will be invited to apply for his State Pension in February 3 months before he reaches his state pension age, In answer to your questions;
1) At the same time as applying for SP he needs to apply for Guarantee Pension Credit to get the SDP, I assume he receives the daily living component of PIP.
2) HB and CTS will carry on, if awarded GPC then he should get full HB and CTS.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems