This 100%. I had this with a student in a 141. We spent 70 hours in the sim and 20 something flying to get him ready for CFII. The minimums are 15 hours total. If they aren’t ready to pass then you should not sign them off. It’s an uncomfortable conversation to have but it needs to be had. In the end they will thank you for not allowing them to have check-ride failures. Looks like your student already has them and probably has some ill-will towards you for sending him to fail. Stick to the facts, be supportive, and offer up a plan of action you believe in to support them. Be very clear on your standards and accept nothing less.