My Friend (male) Is Having Legs Cramps Nightly And Even

My friend (male) is having legs cramps nightly and even on occasion, he said he could see a tendon protruding from front of leg and also at times the muscle pain would go all the way from the calf muscle to the groin muscle.
He is rehabbing a house and has been lifting and climbing ladders etc. often and that is what I think is causing it. What do you think? He does not drink lots of water. But, the protruding of the tendon if what scared him. ANy thoughts?