Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 15 years of experience. I look forward to working with you.
At this age I must concur with you that after a few days of acclimation to his new household he should remain energetic for moderate periods of time. I would also expect a puppy used to other members of his litter to be quite excited to have a playmate again. We tend to only see puppies under 12 weeks of age experiencing the profound sleepiness (they nap all the time) and at 5 months he should have lots of energy. I do think it well worthwhile to have your veterinarian perform a good examination followed by some lab work to screen for possible issues that could include intestinal parasites, anemia, electrolyte problems (low blood sugar, low potassium). If a problem is found, then it can be addressed.
It may also be a good idea to contact his breeder just to find out if any of the other puppies have issues (although the breeder may not admit if he/she knows the puppy has a problem or others in the litter but worth a try).
You appear to be unavailable for a live chat or we are having a difficult time connecting. I am at a point I need to know what questions you have. We can continue our dialog in this setting.
I hope that the information I provided has been helpful.
Please remember to select REPLY TO EXPERT if for any reason you need further clarification, have more questions, or were expecting a different type of answer.
My goal is to provide the best answer possible prior to you leaving a feedback rating.
If you received all the information you needed, then kindly submit a rating.