0719 a senior of my fiance

A senior of my fiance wants to sell his house to my fiance.He spent 4.8 million dollars buying the house 9 years ago.At that time,it was a brand new one.My fiance goes to his house to play mahjone frenquently.My fiance likes the house very much.
The senior now is a major and works at a Lafayette fleet.However he will change his position to Fleet Command where he earns about 2,5000 dollars less per month.What's more,the senior has invested a lot of  money in stock market and some money is defraud by beautiful and young girls.He cannot stand his debts,while keeping the house anymore.He wants to sell the house for 6 million dollars so he can earn money by selling it.
My fiance told the senior that he is willing to buy his house. The senior asked my fiance to rent him a house and my fiance agreed.Much to my fiance's disappointment, I disagree.The senior has worked at a Lafayette fleet where he can earn extra 2,5000 dollars per month for many years.How can he,who has worked for more than 10 years,still save no money?What's more,when he is off duty,he invites friends to play mahjohn at his home.If my fiance rents the house to him,he may cause some problems or fail to pay department rent on time.My fiance begs me because the senior treats him well.When they worked together,the senior took him to nude night clubs and drank everynight.What's more,they play mahjohn often.
In short,I can never figure out my fiance's thoughts.