What on earth do you mean by a therapist may say it as it's their bread and butter?
You mean they lie? Or try to appease a client by agreeing with whatever they say?
What a poor and warped view you have of professionals.
I think you will find that 90% of parents on this thread are saying what I am; don't burden your child with your own sadness. Yes, say you will miss them but putting in a self-indulgent letter and a poetry book is not the way to behave with an 18 year old about to start uni.
For all she knows, he too may be apprehensive and knowing his mum is in bits won' t help him.
The affair your dad had and the impact on you and the family is way off the point. That's a whole different topic.If it still upsets you, maybe you should talk to someone about it? Because it seems to be impacting on your judgement of what is appropriate behaviour from parents.
We're talking here about a boy being made to bear his mum's sadness when he's about to throw himself into Freshers' week, with all the mixed emotions he too may have.