I have an 11 year employee in sales dept...sales have fallen off...I want to offer leave of absence for 6 months...Is his severance affected by this ?

You don't have the ability to make him take a leave of absence. That would be a termination and you would have to pay him full severance. On the other hand, if that is something that you mutually agree to, it has to be very specific and in writing. The bottom line is that if you tell him that he won't be working for 6 months, you are terminating his employment. I am happy to discuss this with you.
Lior Samfiru