First of all JB - keep your chin up. You have helped me more than anyone since I joined this forum and it is your ExH's loss. I am sure what ever you decide to do it will be for the right reasons - and if your son is anything like you he will see your point of view.
I would suggest talking to your son about this ASAP so whatever the outcome the 'damage' will be minimal. If you do decide to go (witch I hope you do) just be yourself. Dont worry about an escort or anything like that - it may work to your advantage for that 1 night, but it will work against you in the end.
If you want me to come then I could use the company too
Mark x