10 year old tires ok for highway driving?

10 year old tires in AZ would be black powder on the ground. my dad had 5-6 year old tires in his beater work truck (spends most of its life sitting in his back yard and is only driven about 2-3 times a year) wel to go use it the other day to run to home depot to get a sheet of plywood, and as he drove away he left the treads behind. they looked just like the retreads when the tread comes off. then he called me begging to barrow my 3 week old (to me) 2006 hemi ram. so he could get his plywood and i said come get the keys. (it had allready pulled the duster and my 04 ram and had seen more car parts in the bed in those 3 weeks than my 04 saw in the 5 years i owned it.