It's entirely understandable that the son would raise concerns and appeal for support. They're his parents and he is quite naturally very worried about them.
It's possible to feel very sorry for the family while recognising that this is a mess entirely of the couple's own making. They chose to go to Iran, despite the warnings and the very well known risks. And not only did they choose to go, they went round trying to "interview" Iranian people, which was inevitably going to raise suspicion.
I hope they will be released safely very soon, and of course the government will have to advocate on their behalf, but it really is incredibly frustrating that taxpayer resources will be spent digging this couple out of a hole that they should never have chosen to climb into.