Whatever the finer details of each complex and convoluted lie he is either a first class bullshit artist (to use a good old Aussie expression) or he has a serious psychological condition and may well be a pathological liar or perhaps there are signs of manic overstatement? Possible signs of Bipolar Disorder? Are the lies just grandiose overstatements or are there other more hurtful or damaging lies?
How your daughter copes with this is up to her. How you cope as a parent in law is incredibly difficult. You see the issues but it is your daughters life. Have you discussed this with your daughter? How is she managing? Are there children involved? What is the impact on them? There are no easy answers. I would suggest that your daughter needs to seek professional help and assessment if her husband will agree.
What did you you think you would have by your current age that you don't?
Only 50% of middle age adult manage more than 1 brisk 10 min walk a month.
Good Luck to your daughter
Even £25 is less than what I have to pay.