at the end of the day he needs to work out his priorities. Meeting up with mates and risking his visa being rejected, or staying put and wait for the visa
you can only get a 90 day Non-O visa now. Once you are inside Thailand and have money in a Thai bank for 2 months you can apply for a 12 month extension of stay and get a multiple re-entry permit so you can come and go as much as you wish during that time
You risk your application being rejected. They can ask for proof you remain in the country you applied from or even call you in for interview. Time your application so you can remain in the country you apply from until the process completes
It's very difficult, if not impossible, to get a Non-O visa as a dependant of someone on a Non-O for retirement now. Some embassies will still do it if the primary person gets a Non-OA visa.