Trading properties is a healthy thing that rehabs homes and whole communities.

This dragged on a bit, then I asked if he'd be interested in a trade instead - we needed the interior of our other house painted so we could list it to sell ASAP.

The LLC will provide some protections of personal assets, but there are also trade offs. 

I would say to him to put it into multiple syndications efforts with experienced investors and if he wants to get into real estate use his own money for that until he learns the trade.

I worked for a trading company once, and they had a finance company subsidiary set up to do loans that normal banks will not do, and probably won't look at yours since you don't even have a background in business yet.

Make sure you keep cash reserves, construction and all trades in general are SKY HIGH right now. 

Yes, your rents may slightly be lower but in my opinion it’s worth the trade off.

Look for other rentals, 2-4 family that have traded and what they were getting in rent.

If you throw out offers to get them accepted and then back out or re-trade the deal, you can develop a bad reputation with the brokers and may be left out of future deals. 

I also had multiple brokerage accounts and a K-1 in a publicly traded partnership (not real estate-related).I have to agree with others that an LLC doesn't provide any tax benefit.