Ok, so you have about 42T on the small ring.
Thus, your crank definitely IS NOT 144 BCD (or larger).
I'd guess that it is probably 130 BCD, unless it is some oddball.
Fortunately 130 BCD is one of the most widely supported sizes. Depending on your Father in Law, I'd probably find something like a 39/50 or 39/52 ring set.
There should be a great variety of rings available. Some with drilling.