What can my boyfriend do? on 2002 GMC Sonoma

My boyfriend has a 2002 GMC Sanoma. He heard grinding and popping noises in the engine. Also, recently the lower ball joint needed to be replaced for months but didn't have the money. His dad is helping him and apparently the only way to fix the truck is spending 2 to 4 grand which I find unreasonable and ridiculous.

Asked by for the 2002 GMC Sonoma
unfortunately when dealing with trucks, suspension repairs never cheap. he can replace ball joints himself with solid instruction, but will need wheel alignment right after. is grinding noise when engine is running at idle or when in drive? this important to find out so he should get a diagnostic run on it first. if no grind noise at idle than possible issue with drive train. popping sound alone would be ignition issue. better to get diagnostic run.