The regular TR will be simplest depending on how long he wants to stay.
He can stay with you but it will help if he has an invitation letter from the property owner and a copy of the housebook. No idea what will be happening with ASQ by then but probably still required in most places.
Make sure he is fully vaccinated. It will make things easier if he wants to do a border run or maybe visit other places. If he is flying this far, he might as well pop over to Singapore, Vietnam or Hong Kong along the way.
Sort of mixed here. If you are getting paid overseas and working online for the foreign country, you would probably be OK. Working in a Thai facility for the benefit of that facility could be a problem.
That is what I did. Print it all up and put it in the mail with a return envelope. I don't mind going to immigration but the tirak is convinced I will get covid in the big city. Still, the stamps are much less than the petrol.
It looks like Afghanistan is being covered by the Embassy in Pakistan. I would start by calling them. Maybe a Thailand Elite visa? It would be expensive but eliminate a lot of visa issues.
Royal Thai Embassy
Plots No.1 - 20 Diplomatic Enclave-1
Sector G-
***
Islamabad, Pakistan
Tel. (92-51)
*****
70 - 80 Ext. 1122,1166 For Visa Section, Ext. 1112 For any other information