While it would be illegal to suspend or terminate an employee BECAUSE they have diabetes or any other medical disability, it is never illegal to suspend or terminate an employee for misconduct, even if that misconduct was triggered by the disability. Disabled employees are held to the same standards of conduct as all other employees and are not insulated from adverse employment action because they are disabled. For an obvious example, someone who suffers from kleptomania (a mental disability that results in a compulsion to steal) can be fired like any other employee if it is discovered that they are stealing from the cash register. The fact a disability caused them to commit this act does not mean the employer cannot fire them for it.
Regretfully, this means that if your brother has been suspended for making an inappropriate hand gesture or for other conduct that was inappropriate at work, that suspension would be lawful. A termination
would be lawful on that basis as well.
The law does not regulate how long an employee can be suspended for. A suspension could, in theory, last indefinitely if the employer so chooses. So, all an individual in your brother's circumstance can really do is continue cooperating with their employer and waiting for the situation to resolve. He cannot compel his employer to take him off suspension, and this is not a circumstance in which he has any legal significant legal leverage.
I hope that you find this information helpful and am genuinely sorry if it is not what you were hoping to hear. Please do not hesitate to let me know if you have any questions or concerns regarding the above and I will be more than happy to assist you further.
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