I appreciate your concerns. It is crucial that people who have a terminal illness receive support when they need it and with the minimum of stress. That is why I support a benefits system which reduces stress and anxiety for people with terminal illnesses. 
As you will know, the rules for terminal illness were put in place to provide important support to people who have only a short time to live. This is achieved through guaranteed entitlement to certain disability benefits, with claims dealt with in a fast and sensitive way, and without the need for a face-to-face assessment.
The policy of a six-month timescale enables the benefits to focus support on individuals in the most severe circumstances where there is greater certainty around their prognosis. However, the six-month rule should be determined by a 'reasonable' expectation of how long someone is expected to live. This approach means, for example, that around two thirds of the PIP caseload who are terminally ill have been receiving benefit for six months or more. 

Everyone with a terminal illness prognosis should be treated with the utmost sensitivity and care which is why staff involved throughout the benefits process receive training on how best to handle claimants in this difficult situation.
I hope this answer reassures you of the safeguards currently in place for people with terminal conditions.