Red Robin Tree - in need of advice

Morning everyone, I usually roam the site but joined specifically to get help for an ongoing problem. Hopefully, someone will be able to assist.  We have a red robin tree, purchased last year, so it's been in the ground and thriving for almost a full year.  We followed the advice from the centre to water it daily in the first year, and everything seemed to be going very well. 

We had that hot spell in May, and it started to bloom, but the leaves were drooping, so we continued to water is daily thinking maybe with the sunshine it needed some extra support.  However, the leaves turned from green to red, drooped some more resulting in the tree now being almost bare. Yet I know it is still alive, if I pull a section of the branch off, it's still green.  We thought we'd overwatered it.  So backed off with the watering, but not a lot is working.  We put some food in the soil as well to maybe help, the plants around it are thriving no real evidence of disease. Scoured the internet for ideas, we don't want to lose our little tree. Can anybody help with some advice, please? Feel we can still bring it back to full glory.