Should you trust an old dishwasher?

A friend just moved in to take care of his elderly father. The father was the original purchaser of his condo 30 years ago and has never run the dishwasher. My friend asked me if he can trust that the old seals and gaskets in the dishwasher to not leak if he starts using it. (The condo unit is upstairs with another unit below, and the concern is that a leak will an issue with the neighbor below.) Any advice?

the only way to know for sure is to fire it up.  Remove the bottom panel so that you can see underneath.  Have a shallow baking pan handy, that can be slid under the areas, in case of leakage.  Start filling and watch for leaks (use a work light or a flashlight).  If any leakage is noticed, stop the cycle.  Use the baking pan and/or towels to take care of the leaking, until it stops.  Note where the leakage is from.  Is it just a hose fitting or is it from an assembly and is likely a gasket?

If no leakage, continue the cycle, keeping an eye on it for leakage.

Take it for a dry spin.

Take off the kick plate and without loading it turn it on and observe. If there is a leak just turn it off and have it serviced, if not, load it up and enjoy it......

Yes they're right, get it to a test and observe first. If it's not working well, investigate first what causes the leak or anything.