My brother is employed in a training company that would like to give a presentation about its services to CERN. May I give him the name of the responsible person at CERN he should contact?

Yes, as long as you do nothing to influence CERN’s decision to retain the services of your brother’s company. You should inform the respective CERN officer of your relationship and clarify that your input should not be seen as interference in CERN’s decision-making process