Dont think regulations are helpful. Its the controllers experience and inteligence what can in these situation help and also often save lifes. I have experienced several of these situations in my ATCO careers.
So back to the quesstion: of course in certain parts of world IFR in uncotrolled airspace is a daily life..flying IFR in G class airspace is allowed for example in the UK, Poland etc....hower nothing change regarding my previous post...you can be cleared as an IFR flight...but you HAVE to maintain or be above certain altitude (MRVA,MEA,MFA,....)
Providing a help to VFR flight entering IMC Is a slightly different topic then ....ATCO in that case follow the checklist and giving the pilot aid by describing the close enviroment ( basically giving a MFA/MRVA etc...)...Then if the ACFT and pilot is allowed for IFR..And at/above the MFA/MRVA etc..he is cleared for IFR flight.