In most states you need a full Brokers license to do property management. In Texas that means you have to work as an active Salesperson for four years before taking your Brokers test. I agree with @Elizabeth Colegrove that most of the stuff you learn has nothing to do with Property Management. You won't even be able to write a lease because all contracts in Texas are required to come from a licensed attorney unless they are provided by a principal or the TREC.
One option for management of family rentals might be to buy 1% interest in each property which would give you the property owner exemption. This would hinge a bit on family dynamics, but if people OK with having a relative as the manager the 1% ownership is probably a safe option too.
if taken to task the 1% ownership as a ruse to get around licensing rules will not hold up.
But hey if its family what is the risk anyway.. States in general are not interested in small timers.. its the blatant disregard for the licensure that gets the attention of the states. IE companies holding them selfs out as PM without a license or some mom and pop that has 30 to 50 homes under management of which there is no familial connection.. those are the ones that get rooted out over time.