Andy is a very down to earth guy. he took a liking to Lendl for what he brought to the table.
Lendl has a wealth of experience. he had been in no less than 19 grand slam finals. he had done well at RG as well. so there was more work to be done. Lendl could have offered great advice for clay.
Lendl worked out for Andy. so this is a huge loss.
evidently Lendl made an impression on Andy's family.
I hate to see Lendl go as well.