Yes, I have plenty of clients who have multiple rental properties in their name - whether residential or commercial. There is nothing wrong with that. They might want to put the properties in an LLC or an S Corp for some tax and liability considerations eventually, but what your friend s doing is totally fine.
The information provided in this answer does not create an attorney-client relationship and is not considered to be legal advice.
You can reach Dave Rich at (303) 886-2516 or email@example.com. Dave Rich is an attorney licensed in Colorado. Answering your questions does not create an attorney-client relationship between us. You should speak with an attorney to whom you have provided all the facts in your case, before you take steps that may impact your legal rights. I am not obligated to answer subsequent emails or phone calls unless you have hired me. I wish you the best of luck with your situation.