When he is your Libyan tour escort.
As explained very clearly in the Libya Guide in the excellent website maintained by the Temehu Travel company, Libyan rules require all tour companies to provide a company representative who must accompany you as you travel through Libya. Although this person is always referred to as a"guide" by tour operators, he is more correctly an "escort" or "companion", in Arabic the word translates literally as "he who accompanies you".
Most of these escorts have no professional qualifications as guides. They are employees of the tour operator or the travel agent who, by law, must accompany their visitors during their tour or stay in Libya. Confusion can arise when visitors expect their "companion" to fulfil the role of a qualified, well informed guide. This is not his role. He is there to faciltate your journey, deal with hotels and transport arrangements, pay the bills at restaurants, buy the tickets at museums and sites, etc - and where required, to pay the local archaeological or museum guides you have requested.
If you want such guides at any point of your visit, you need to specify this clearly when arranging your visit if you want the cost to be included in your overall payment. Should you not stipulate this at the outset but change your mind later, most museums and archaeological sites have guides whom tourists can, and sometimes must, hire but you will have to pay the additional fee yourself.
Please bear in mind that Libya was for many years a closed country and has only recently begun to experience an influx of tourists as the world becomes aware of just how much it has to offer. Tourism is still very much in its infancy in Libya. You are coming at an exciting point in this development and have the privilege of experiencing its extraordinary sights, culture and history with very few others to share it with. It's not going to be long before that changes as tourism expands and numbers of visitors grow. Be understanding and respectful of the status quo. Your companion has just one main focus - that you have the best visit to Libya that you possibly can have, and he will work very hard to make sure this happens. Your acceptance of this requirement and understanding of his role will go a long way to making it a great experience for both of you.