You can use this property to hedge any others that you add that may only cover themselves, or require supplement until they are paid off.HOWEVER, if you have decided that your goal is to use Real Estate as a stepping stone to build wealth by upgrading the property you hold each time (condo to house, house to 4-plex, 4-plex to 8 unit, etc) then I think you are right to sell now while you think the property is at the top of it's appreciation.It will be hard for anyone on BP to tell you what to do as we don't know your goal.You are right. 

But on the other hand, even that one single duplex you bought 30 years ago would provide a really nice supplemental retirement income today.

I like to keep things simple in my business, and I have no desire to represent buyers or sellers - that's a completely different skillset than wholesaling.It is similar to asking why a doctor wouldn't also want to sell supplements - some would, in order to "better serve" their patients and create an additional revenue stream, and others would rather keep things simple.

The purpose for this property will be to supplement their long term care. 

What I personally would like to do is set up a type of Trust for my family (3 households) that will buy and hold property to create supplemental income amongst the three households (families) and ultimately form a type of generational wealth long term for our children.

We have to focus on nutrition, removing toxins from our environment, and get her body healthy enough that it can start fighting back again.If you know someone with cancer, or just want to educate yourself on the truth about chemo vs. nutrition, check out chrisbeatcancer.com or the book, "Chris Beat Cancer" by Chris Wark.

Supplement that education by obtaining a “diploma, certificate, degree” from a major college 3.

Special financial assistance and loans to rebuild, survive rebuilding phase, short-term housing supplements and units, things like this. 

I have been learning to have a very vigilant eye on ingredients and nutritional facts.

Suggest you get your real estate license because highly unlikely you can make a living off of 10 units - unless they have no mortgages on them.Even then, taxes, insurance, maintenance, vacancies and nonpaying tenants will make it difficult.So, you'll need to do wholesaling, fix & flips, or be a real estate agent for other investors to supplement your rental cashflow.