Please advise with tips or suggestions, alternatives. 

Nature vs other. 

Your local LL tenant laws may also have provisions for removal depending on the nature of the offense.

Naturally it's not reasonable to try and hold the management company or even a Landlord responsible for someone trying to break in to the property. 

Unlike Europe, the US has plenty of land and natural resources.

The bank is asking for 20% down investment in a duplex. How can I get around this for my first investment.

In addition to 5 years of paying on a 15 year, we have put a lot of upgrades on this property and there has been very nice natural appreciation on it. 

Alternatively you can obtain clear title after 20 years of using the property if you do not have "Color of Title" (if you had mere possession and did not lease from the son or pay him any portion of the rents).Color of title would be a deed from someone (the son) who you have reason to believe had the right to transfer the property to you. 

Alternatively, I could sell the property.

I was raised frugally, so I spend little by nature.