The answer to your question depends somewhat on the preferences of you and your son's surgeon
). Your son will need to have his own nephrology and surgical consultations before that transplantation can be scheduled. I think that since he is agreeing to give up an organ, that both of you should be present for all the consultations. This is just a personal opinion, not a medical opinion. The reason I have this opinion is that this is a huge decision your son is making and both of you need to have all the information possible so that all the risks and benefits of the decision are known.
I suggest that you discuss this issue at your next appointment with your nephrologist. It may be a good idea for you and your son to have the same doctor. This way there is only one cook in the kitchen. Your doctor will be able to give you his or her opinion on how the appointments and evaluations should be carried out. Having your son there will be helpful. At that appointment or a separate appointment your son will need blood work and imaging done of his kidneys to insure that a living donation is possible. Good luck.