Accessing support for employment

My 21 year old son has been in and out of employment since finishing college 3 years ago. He completed an NVQ level 2 in sports coaching but has never managed to secure a job in this field. He has had a range of jobs some of which haven’t worked out because they required him to carry out tasks that he struggled with because of his dispraxia. A job in a warehouse was more suited to his skill set but he  lost this job due to his immature behaviour (trying to make his colleagues laugh!). I really feel he would benefit from having a ‘mentor’ who could accompany him to work until such times as he has learned the role and understands what’s required in terms of workplace behaviour. Has anyone managed to obtain this type of support and if so how did they go about it? Grateful for any advice or suggestions.