Hi, I have RA, from my mid twenties that things got bad enough to end up being referred and diagnosed, I'm 38 now. I've been on quite a few meds, Sulfasalazine then Hydroxychloroquine, Methotrexate (tablets then injection) then on to the biologics, Tocilizumab, with and without Methotrexate, then Etanercept (Enbrel) which I'm on now. Lots of steroids in the meantime, oral and both general injections and various joint injections too.
Like bednobs, I couldn't tolerate Methotrexate but many do without issue. There are also ways to help with some of the side effects if he gets any. unIt does seem daunting at first, especially having your immune system compromised, but you really do tend to get more relaxed about it once you're on it. There will be regular blood monitoring to pick up any issues early on.
It's good to have a good GP for extra support and quick access if needed, for example, should any infections crop up.
The specialist Rheumatology nurses can be a brilliant help too, some can also do things like give steroid injections, which is great as it reduces the wait to see a doctor.
Have they given him any information about a helpline? My department has a helpline you can ring and leave a message for a Rhumo nurse to get back to you, can take a few working days but it can be really useful. From forums it seems to be fairly common to have this so good to check if there is something similar available if he hasn't been given any info previously.
There is also other support from departments like Occupational Therapy and Physio should it be needed in the future, I've also had help from Podiatry, Orthotics and the Pain Clinic too. So there is help out there going forwards. Good to know even if he doesn't need it.
There are lots of support groups on Facebook for people with RA if he would find any of them helpful at any point. Feeling nervous about going on Mtx is a common question and good to hear from others who have experience of things.
There is also an Expert Patient programme which is worth looking in to for the future. I did a similar one but specific to Fibromyalgia, which was great. Can be difficult with working too though, depending on the hours it runs locally. An example here:
http://www.srft.nhs.uk/about-us/depts/renal-services/pts/the-expert-patients-programme/
Diet wise, I've found no diet which helps. I was told at a Rheumatology patient information day (another good thing to check if his department does, it was really informative!) that in their experience no diet helps with RA.