A collapsed lifter is not serious as far as causing other damage. It is not uncommon for them to bleed down while the oil is drained out, then a few can take a while to pump back up. I had a 1972 Dodge that had one lifter that rattled after every oil change until I drove the car at least 30 miles at highway speeds. That went on for years with no other symptoms.
The common failure items that cause stalling on any car are the crankshaft position sensor and the camshaft position sensor. Sometimes it takes a while to set a fault code, so if there is no code, there are other ways of diagnosing this. It is important to not disconnect the battery or let it run dead now. Doing so will erase any codes, then that valuable information will be lost.
By your description, it sounds like you also had the transmission default to "limp mode" where it goes to second gear and stays there.
"My brother took it for a test drive and we got it up to 30 mph with a rpm of 6. It sounded like it did not want to shift"
That's 6,000 rpm which is hard on any engine. Do not let anyone do that again. Limp mode is meant for you to be able to drive slowly to a repair shop without needing a tow truck. There are actually people who drive repeatedly over 60 mph in limp mode, then they blame it on the manufacturer when the engine flies apart. Duh!
There will be a fault code in the transmission computer to tell why it went to limp mode. We are not going to worry about that until the stalling problem is solved. The two can be related.
Thursday, June 16th, 2016 AT 9:36 PM