After someone has failed the Work Capability Assessment, they will be in the All Work Requirements conditionality group (unless they are a full time carer of a disabled person, main carer of a child under 3 etc). This is the case even if they are challenging the 'fit for work' decision.
However, if the claimant has health problems, they are considered to have Complex Needs and the Work Coach should take these into account when deciding what the Claimant Commitment should include. The Work Coach or Case Manager should make a note of the health condition on the Claimant Profile. If the claimant's health condition is long-term, the Equality Act 2010 might be relevant, and reasonable adjustments might need to be made.