Dog acting strange lately??

Hi all wondering if anyone has had similar problems with their staff.
I have had cheeko for 10 years since he was a puppy.
He has always been a good dog excellent with my 3 kids and my very best and loyal friend.
My mums staff passed away 6 months ago (bless him) he was 12 and was good friends with cheeko.
My mum has a new puppy now who cheeko likes but doesn't seem to know if he is male or female (stupid??)
I recently went on holiday for 2 weeks I don't often leave him but if i do I leave him with my mum.

For about a month he has been whistling at me constantly asking to go to my mums I think to see the puppy? But he just violates him if you know what I mean
When I left him with my mum he howled for days for me.
If I leave for work he howls the house down.
I love him with all my heart but this constant hassling is really wearing thin now.

My wife and kids are mostly at home so it's not because he is himself a lot.
I'm guessing he is either grieving for my mums late dog or he is sexually frustrated?
He has not been neutered as a pup but never had anything other than silly behaviour for a days when a bitch is on heat nearby.

Any suggestions appreciated

Thanks

That does sound strange, can't really advise as not something I've had to deal with. My only thought would be that perhaps a vet check up would be worth while to rule out anything physical?

Aww he doesn't sound happy at all, I agree with saz a vet visit to be sure everything is ok