What products, if any, can you recommend for a dog that is urine marking in the house.

A little background which I think is important.. My grandson adopted 2 dogs a couple of years ago from Tall Tails Rescue about a year apart. They were both very shy with strangers (almost fearful) but have come around somewhat. Back in May my grandson had to move back home and lives in the lower level of the house. Leo and Diesel have adapted well thanks to my daughter who has gotten them into a routine. However, Diesel is urine marking in the house. Right now there is only one recliner downstairs because Diesel chewed the sofa down to the frame. He has also chewed blankets and an area of her wood molding.

I guess I should mention that he is a hound dog (not sure if pure bred) and he is neutered. He has been checked by a vet and there does not appear be anything wrong with him physically. Not sure if this is important but both dogs are by themselves for a good part of the day. My granddaughter lets them out at lunch time before going to college.

Diesel obviously has a behavior problem and probably needs professional help which they cannot afford at this time.

In the interim do you have any suggestions?

Are any of the otc products effective (either plug-ins, supplements, etc.)?

Thank you