To follow from that good answer, it is incumbent on the employer to therefore ensure they have appropriate policies, training, in place such that consideration is made in recruitment and working environments such they satisfy the Act. Disability is an analogue condition, varying in many steps from extremely mild at one end of the scale to extreme at the other. Unlike sex discrimination, which is digital (you can count the number of males and females in a set or pool of workers and make comparisons), there is no right answer to what an employer has to do.
Unfortunately, if employees and the employer can't agree, the ultimate arbiter are the courts, who adjudge whether the keys words in the legislation - 'serious' , 'long-term' and 'reasonableness' of employer's policies, actions have been breached.
You are going to have to say a lot more about the specific scenario to be able to comment further.