With the symptoms you are desicribing and how much he drove it too hot and kept doing it..you can pretty much count on that aluminum head being cracked and warped to hell and back.
And as many times it has gotten that hot,he'd be lucky if the rings werent shot and scarred cylinder bores.along with bearings being wiped out...etc etc..
Best thing to do at this point is pull the head and have it checked ..but if i was to try to fix something that went through all that,i'd seriously be considering a new reman engine or rebuild....
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