Unfortunately there is no real reliable way to do this. In fact, 4K LG to date have not been very reliable in terms of control and have actually taken a step back from its 1080p predecessors. Using general commands, you may be able to string some together to achieve what you want. However, this would be considered a workaround, and due to the quirks and pitfalls of Smart TV, it might not work at all under certain circumstances.

Most if not all TV manufacturers have done little in terms of allowing for control of Smart TV functions. Sharp seems to have the best API for means of app control, but nothing very comprehensive. At least you could save some apps as favorites and launch them via IP.

My advice would be to not make a bad situation worse. Unless LG can come up with some API that would allow for better integration you might frustrate the customer before you make them happy.