Everything i said your photo confirms. You get issued the visa by the Thai Government and have to use it within a certain time. If its a 6 month visa the clock starts ticking the day you first enter Thailand and not the date it was issued. The date you must enter Thailand is within a certain time from when it was issued.
I've just reread and see he doesn't want to use the METV for his initial trip. I think he can even just artive without a visa and get stamped in for 45 days and extend that for a further 30 days. He then needs to do a border bounce and can come back in again without a visa for another 45 days plus get another 30 days extention. Suggest to put your mind at ease you ask this question on the group Thai Visa Advice as the moderators are very clued up.
The visa lasts for 6 months from the day he enters Thailand. So if for example he enters 5th May his visa lasts until 4th November. If he enters Thailand on 4th November he will get stamped in no problem for another period (60 days i think)
Opening a bank account is the very best time to use an agent.... If in Chiang Mai i used Thai Visa Assist and it was so easy. I was on a tourist visa at the time living week by week in serviced rooms with no contract.