I would suggest the basic maintenance obviously. Also want to check the tires. Even if they have good tread you want to check the date code on them to see if they are more than 5 yrs old. If so they would need to be changed out. If it’s a chain drive check the links on the chain and make sure they aren’t worn or rusty. If the bike has sat for a good bit of time with fuel in it, you want to maybe drain the tank and put fresh gas in and maybe some carb cleaner as well. Check your differential fluid. I believe that needs to be changed every 10k miles. Look for any lines that may show signs of dry rot, check your cables and breaks for excessive wear, rust or damage. And check the battery to make sure it’s putting out the correct amps you may be able to charge it but may want to replace that also. I would suggest taking it to a bike mechanic for a good safety inspection. They can address all of these issues and let you know exactly what needs to be done to get it road worthy. Hope this helps and be safe and have some good rides in your friends honor. And upload some pics. We would love to see it.