When my rental income is filed on form 1040, it's attached with Schedule E:  Supplemental Income and Loss. 

I'm trying to learn about the world of real estate investing through books and am hoping a degree in finance can supplement this "career". 

To avoid to pay for the supplemental tax?

As @Ronan M indicated they are common for years in other parts of world (I see many in Europe where the heating is often primary radiators (no ducting) with Splits providing supplemental heat and AC. 

I was lucky and found a brokerage that was started by a couple who were investors first then the wife got her license as a way to supplement their investing business. 

My goal is to own buy and hold properties in order to create a passive income to supplement my income.

INERPRETATION: This Addendum supplements the terms and conditions of the Lease.

My initial thought is to eventually buy him a condo and provide him with enough dividends from investments to supplement his current income.

These Rules and Regulations are not exhaustive and may be supplemented or modified from time to time upon written notice to Tenant."  

I think in conjunction with any supplemental education you seek, I would also meet local professionals that have been doing what you are looking to get into.