This is a very good idea. In the medium/long term you are quite unlikely to find a better investment (better defined as a combination of risk and return).
I've been a landlord with investment property at various times over the past 30 years and the only mistake I've made is to sell the properties, should have kept them. (quick edit: we had some flats in London at one time, over 25 years they've gone from £300k to £2m (we sold way too early unfortunately) - so you can make a lot of money, in the 1980's 300k was a lot but it's clearly less than the £2m now inflation adjusted etc)
You don't need to set up a separate company to do this. it is worth having a written agreement between you and your brother, what happens if one wants to sell, what happens if one cannot afford bills for repayments, what happens if one of you passes away etc.
FWIW when we ran number of properties we paid a specific individual to look after them, on a single property we paid the agent to find the tenant but then no monthly payments as we managed property and we are capable of calling a plumber and don't need tp pay an agent 15-20% (inc VAT) to do that for us.
By reference my daughter has just started a job in Leeds, she's in a house-share with 3 other professionals, we estimate the rental yield is over 10%. If you are doing calculations you need to look medium/long term IMO and look at capital gains/paying mortgage down rather than short term income, a buffer of rent over mortgage interest is essential as interest rates will probably go up faster than rents in the next few years.
I strongly suspect a very large portion of investment properties don't appear on a tax return.