Hi beth819.
I am sorry to hear about your bed bug infestation and I can certainly understand your concern and distress. Some of the information on our forum about this issue is in the thread that you’ve already activated (with the links it leads to)
As you move into a new environment, the “safest method” would be to get new mattresses, but it looks like you’d still need to deal with your dad’s room(s) infestation and then you’d have to part ways with two quite suitable mattresses that are a long way away from reaching their useful life. I’d say that because the bug extermination is done by a professional the chances are that with an appropriate encasement you’ll also be able to safeguard against bug population regeneration. I’d probably ask the bug exterminator you are working with if they can combine a few methods to achieve the best results. Heat treatment is quite successful and many pest management companies that specialize in bed bug control will use something like high temperature steaming as part of their process. The steamers have large heads which are used for treating mattresses, inside box springs, and any upholstered furniture … it is a slow and methodical process that may take a few hours to complete but it seems to be successful. I know you did a great deal of research but you may also wish to comb through some of the info and readings here as well. Once the treatment and sanitizing are complete, as the exterminator mentioned, you’d certainly want to encase your mattress in a good quality bedbugs encasement that prevents anything from getting into it or escape from it and that does not tear easily. I’d look for an encasement meant for this specific purpose that has a locking zipper which won’t allow the bed bugs to escape or enter. The better ones have a membrane which are less breathable but this would be the tradeoff for bed bug protection. There is more about mattress encasements in post #2 here and in post #2 here that you may find useful.
Phoenix