2001 ford explorer wheel locked up
 

this is a 2001 explorer sport v6 4x4

so my moms boyfriend called me today apparently his front wheel started pulling to the right for some time, then it locked up while he was going 60mph down the road. his tire poped and his spare was flat. He had some one meet him with the spare (hour later) put it on and drove it to his baseball game and back home with no problem. (hour drive)

I told him its probally a frozen caliper, but I thought it was very weird he drove it around for some time after it locked up with no problem.

could any thing else cause this

I told him not to drive it and get it towed to a shop but he seams to think its no big deal.