The black smoke might be related to turbo oil seal failure or a problem with the injectors. It there is a serious issue with the injectors then your brother may be facing a huge bill to get the van up and running. The low coolant and oil levels are a real concern, however, as it suggests the van has been neglected and this usually means serious mechanical problems are not far away. If your brother paid very little for the van then it might serve him well as a cheap workhorse for a year or two. But it reads like this van is nearing the end of its mechanical life. If you need to find a local and trusted mechanic, try our Good Garage Guide: good-garage-guide.honestjohn.co.uk