1, You internally transfered on 4/1. At that time the probation period is 6 months, in your case the probation period ends in 10/1. You were let go on 9/13, still in the old probational period.
On 9/1, the school changed the probational period for internal transferred employees to 3 months.
But you didn't supply the ORIGINAL TEXT of the new policy. The policy could say "applicable to all new internal transfers after 9/1", then it doesn't apply to you. If the policy says "applicable to all internal transfers who are still in probational period as of 9/1" then it applies to you. You have to understand legal text is very important to determine the outcome of the case.
2. "He thinks he was wrongly terminated. " What is the basis of your reasoning? Just your own logic or logic based on actual text of the policy.
As for legal fees, lawyer requires fee to be paid ahead of time, EXCEPT in personal injury cases. Again, you think you should pay only after winning is your own fantasy, not based in reality.
3. Conclusion
In both probational period and legal fee cases, I found that your mental process is not based in reality but based on your own internal logic what what society SHOULD BE, not what society actually is.