Be aware that the dual bander radios available today really are only one radio. You can not receive but only one signal at a time. Same with the transmitter. Only transmit on one frequency at a time.
Yes you can scan both bands, but the first signal in stops the scan and until the signal goes away, you won't hear anything else. This dual band radio push is not all that the radios are hyped up to be. Plus the vendors are demanding top price for these toys. Personally I would stay with 2 radios for now.
LOL, he is not wanting a ham radio! Could not legally use one anyway for his use.
People in Public Safety like the OP have an entirely different use for the radio than rag chewing for hours.
I am willing to bet that most amateurs with the dual band V/V U/U V/U dualbanders use the mute feature of the unselected band anyway. It is very annoying and be tough to listen to 2 conversations at one on a portable.
As far as the comment "they only transmit one frequency at a time". no comment LOL
The point is that Dualband radio's for Public Safety serve a valuable purpose. And is not a bunch of hype. A great tool for interop.
I would recommend the APX7000, they are expensive, but he can save a lot if he does not need P25 trunking and other features in the radio.
Some others have mentioned some other radio's that may be viable options. But you do get what you pay for.
With the APX and the others scan works just like a mono band radio. Scan with Priorities across both bands in conventional mode.
I hope the OP finds what he needs in the price range he can afford.
Let us know what you decide.