Perpetually exhausted husband driving me to the brink

My husband and I have two young children (3 and 1.5). We both have stressful full time jobs - though I mostly am able to work from home. We both work a significant number of hours a week (50-60) but have plenty of support and childcare.

My husband is constantly exhausted, and it is driving me insane. He is capable of working full time, and can take the kids out and about, engage with people, etc. However, when we are home - he is always sleeping. Last night, he went to bed at 7pm (when my toddlers did), woke up at 6:30am, and is now napping at 1:00pm alongside them. I guarantee when they get up this afternoon, he will sit on the couch yawning. This has been going on for years. This dynamic is creating both frustration and resentment in my marriage. He recently went to a doctor who said, ’he needs to get more sleep’, but this feels out of control for a 35 year old man. Any thoughts / help? I am truly at my wits end.