I am sorry for this dilemma
You ask a couple of questions
Can they really do that or should he be given the opportunity to reclassify.
I will try and address them separately.
Can they separate him for this? Yes. They can. Under the rules, if a service member has been on active duty for less than 6 months they are subject to an "entry level separation
". This is akin to being on probation in a job...the employer can release the employee during this time frame if they
"Cannot meet the minimum standards prescribed for successful completion of training (i.e. PT or Weight standards, academic) because of lack of aptitude, ability, motivation or self-discipline."
So failing the same test 2x can be a basis for this separation.
The tough part for the soldier
is they have very little in the way of due process. They are permitted to submit matters in writing to contest this. The matters will be reviewed by the separation authority (the commander who has the final decision on whether to separate or not) prior to decision.
So your son can submit a written statement as to what happened, and why it will not happen again. He is also allowed to submit statements from others in support. So, for example, if his direct supervisor is willing to draft a letter of support, your son can include that as well. Your son can visit JAG at the TDS (trial defense services) and they can give him some assistance in this matter.
But the botXXXXX XXXXXne is that he can be separated for this.
That is a different question. Typically if this is the only stumble it would NOT result in a discharge. So there may be more to the story. It is my experience that the parents often are not apprised of the complete set of facts that lead to disciplinary proceedings. If this is truly a case of failing one test twice and otherwise he has a stellar record? I would (were I him) fight to remain in. If he can get letters of support from his chain of command I would expect the separation authority to consider retaining him.
But if there is more to the story...if he has had discipline problems, or other issues, that could be why he is facing discharge now and would make contesting this very difficult.