You are welcome!
As mentioned before, it used to be NOT possible to change from visa exempt to Non-I Type R.
However, please ask your friendly immigration officer at your local office to make sure.
Non-I Type R visas are not limited to monks only, they are also available for MaeChis, Samaneras,and Pakaws.
I do know a number of monks who have applied for a Non-I Type R from abroad, it is almost the same process as from inside the country.
But as one needs a knowledgeable person inside Thailand to organize all the paperwork, it is more difficult to do.
Abroad, one will be issued a 3 month visa only, which can then be extended by 1 year inside Thailand, (applying earliest 45 days before date of expiry).
The easiest to do for your friend would be to arrive with a multiple-entry tourist visa.
I gather, your friend is not a monk yet, so he would also have more time to try things out and adjust to the monastery/the monks life/preparing documents/etc.
I do apologize for the confusion, National Office of Buddhism (สำนักพุทธ) and Department of Religious Affairs do mean the same thing in my explanation.
The process for -applying for a new visa and the process for -applying for a 1 year extension is virtually the same:
One does need a letter of recommendation from the SamnagPut, with this letter and other documents one can then apply for the visa at Immigration.
To get the letter of recommendation from the SamnagPut, one needs a form called Prawat, which needs to be filled out with personal information and then needs to be signed by: abbot of monastery, local sangha head, district sangha head and province sangha head,
Also, one needs a monks ID Card (called Bai Sutthi), a letter of support from ones abbot and a certificate of residence from ones monastery.