A bank account. Otherwise, this is a very difficult time to invest.
The cheapest asset in the world us US land. But you said you have enough property. If I had to lock up my investments for a decade, I would choose a portfolio of high quality, large, dividend paying stocks.
Which is why I said rental property.
He has enough to buy a couple of decent houses outright.
He then can take the rent he recieves and put that in the bank and use only enough of the cash to repair and rerent the place.
Before long you have quite a little lump sum.
1000 a month for one house is very easy to see.
In five years you have neary half the cost of the house covered AND you still have the house to rent or sell.
People fear renting, its a piece of cake if you do it right and stop yourself from expecting there is not supposed to be work involved.