Parked his truck on the side of the road, was on foot when he was shot in the back by a 15 yr old gangster with a lengthy rap sheet.

Unless these folks are the money managers for a money laundering scheme designed to clean blocks of cash with large denominations and private party placement and don't care about 5% US Bond scrutiny (sovereign wealth comes to mind), my first thought when I saw the 3% interest rate was skepticism.  

Though self-direct rules allow a broad range of investments, these companies restrict you to their stocks, bonds, mutual funds, etc.

Depending on local law, you may be able to get a bond in lieu of probate from a title company if you can tie the brother to the property as the other living heir.

It’s not like buying a Federal government bond.  

Make sure they do not have a high turnover rate.5) Cleaner is bonded and insured6) Yes, it is safe to give a cleaner a key.

Should I invest my money in bonds/stocks?

With interest rates in high double digits, I was easily able to locate corporate bonds of BBB rating with 20 years of payments left and 8-9% coupons.  

They will line you up with several pre-screened, licensed/bonded contractors that do the work you need.

I went out and purchased purchased anold 30 year treasury bond(s) (actually five $10k bonds) with a 5.5% coupon for about $24,000.