Not knowing the chap in question and not privy to the exact reason for his dismissal but employed by same company, I am sure there was a sound reason for the sacking.
I am also sure that BALPA would only help you if there was a question mark over the cause or the method of the disciplinary process .
If there was no doubt to the cause and the process was followed correctly BALPA are not interested.
I have always been treated fairly and I err as often as most. If you are honest open , have a bit of integrity and stay within the bounds of SOP,s you will be OK