Father-in-law in jail - what to do

Calling all Forumosans

It’s rather random and apologise for being vague, but I need some pointers on what to do here.

I am married to a Taiwanese lady and we are currently in the UK.
We have just found out that her Dad, who is in his 60s, has been sent to jail for what appears to be jumping bail for a crime committed many years ago.
I am not sure of the details but it seems to be related to a scam marriage.

My father-in-law has a partner, but she has been told that she can’t see him because they are not legally related, and as such they (the police) have refused to cooperate with her enquiries.

As his only child, my wife will be flying back to Taiwan to see what can be done to help his situation. I will be staying back to look after the kids.

Is there anything we can do before she flies off. A lawyer we can call or maybe a government department where we can get more information on what is going on.

Thank you