We are on holiday and have just been messaged by our friend who...

We are on holiday and have just been messaged by our friend who is minding our dog that he seems to be fretting.
Our minder advises that he eats his food periodically and has lost a bit of weight.
We have been away for 3 weeks and will be home next week.
The problem we have is we will be home for 4 weeks but have to head off again for another 4 weeks.
Has anyone any suggestions on how we can help the little bloke overcome this problem.