Welcome to LQ!!!
Are you sure it is your friend who needs advice not you? No offence and sarcasm intended. The reason I asked because if it is your friend then you should ask him to join the community too. It will not only help him to get advice on certification but he can discuss about other topics related to Linux.
Anyways, coming back to your query, you have not mentioned the exam he is preparing for so I am assuming it is about RHCSA as that is the entry level exam. RHCSA is now on RHEL 7 which is in the market from quite a while but still not many books are there. I would suggest to have a look at the following RHEL 7 guide:
https://access.redhat.com/documentat...uide-en-US.pdf
Apart from this he has to make sure that he has hands on experience either on job or from his test environment. Would like to mention that RHEL 7 is not free, however, he can go with CentOS 7 which is rebuild of RHEL 7 and is absolutely free. Whatever works on RHEL 7 works on CentOS 7 as well.
It will be good idea to have a look at exam objectives
here
If he is planning for self study then going through RHEL 7 administration guide, setting up test lab using CentOS 7 and going through objectives will help. If he has got experience on RHEL 7 then it will be an add on. If he has not got experience and in doubt then I would suggest going for RHEL 7 official training by Red Hat. Training is quite costly and paying money for training for entry level exam hurts. However, directly appearing in exam and not doing well in that will be a double blow.
So, if he is sure about his self learning skills then there is no point going for training, he can directly go for the exam. This is a choice he has to make.
