Money can cause a lot of upset in families so I can see why he has hidden it while he decides how to approach it. I get annoyed at helping my MIL not because I am tight, but because she fritters so much money away and then comes begging for a handout. She lives on benefits and when she inherited some money, she basically lived a year or two buying multiple brand new sets of furniture, brand new car replaced by a brand new car a year later, cruises etc (i.e. a much more extravagant lifestyle than my wife and I in reasonably paid jobs with no children) and lo and behold ended up running out of money.
I guess the real problem is that people have different views on how money should be spent, and when you gift someone a sizeable sum money it is hard to do it in a completely detached fashion in terms of where it is going to go.
I must admit I quite like the 'lock it away in property' idea i.e. clear all debts and move to a nicer house and then you've got no money burning a hole in a pocket but do have an asset you can fall back on in future if times get hard.