Quick neon question for a friend

Hi. My friend currently owns a 1999 2.0 sohc neon. He was wondering if it was worth just changing the head gasket for about 400 bucks since thats all it needs, or drop in a new engine. i say head gasket but he his stuck on the engine swap. any suggestions?

If he is going to swap in an engine, have him change the head gasket and timing belt before he installs the engine, so he won't have to until much later.

Change the headgasket and might as well do the timing belt, water pump, and tensioner pulley at the same time since it will all be apart. If he is close to or over 100,000 miles he needs to do that for preventive maintenance.

i believe that he said that he would have his mechanic do it for him, since he doesnt have the time to do it...makes no sense right? instead of 30bucks, its 400.....

on a second note, i believe he has about 91k on his engine, so those would probobly would be the best things to do. i am not that well known about neons, so i asked. anyother things should he look out for to to go bad around 100k?