She, and her husband who is an Australian citizen, are returning to Australia once they sell the property. 

Unlike a senior community where there are TONS and TONS of seniors and plenty more becoming seniors all the time, your pool of buyers is much smaller I think. 

I use Citizens and its great terms 25 yr with 10 yr draw. 

However, being a Canadian citizen, it seems like I would still need to pay Canadian taxes on the US properties regardless. 

Any opportunity is too good for the law abiding citizen, unless he can bring to table millions of dollars , spend 60 hours on some BS course to acquire a license, to have every breath and sigh controlled, regulated, restricted, obstructed and sabotaged.

They may be a senior and cant afford to live without the help.

Our country has a housing crisis and it doesn't seem right to rent our properties to illegal immigrants when our citizens struggle to find a place to live.

Is there anything I should know about managing senior living rentals/buying in these communities?

Anyone who has Home Owner's through Citizens has to have Flood now if the property is worth more than $600,000 and everyone else next year.

Quote from @Saad Aslam: Hi Seniors,I am a non-U.S. citizen living in Pakistan and I want to invest in multi-family or single-family units in the United States.