Are they considering nonrev as OALs? What are their pass privs like? Can friend travel same as daughter?
How old are they? Are they willing to split up?
BKK is one of the toughest at any time of the year. Better start thinking about LCCs. I think there are several threads on the topic. We had difficulty last year and routed thru Singapore ($$$$ BTW) the used zeds to get to our destination. We're planning to go back this fall and it might be tricky using high priority w/26 yrs seniority. Get back to us and we'll work with you on ideas.