Is dangerous or am i going OTT

[seqo]

A few months back i notice one of the rear exhaust mounts for the back of my is250 were rusting.

I bought a new one for each side for along with a new gasket+springbolts for mid exhaust pipe - Whatever Lexus parts said i needed for the job. I then took it to the garage my dad has had his cars serviced at for years and asked him to replace them for me. +image below, above ONG647 is where the exhaust was taken off so the new hangers could be bolted on.

Few months down the line and can hear an exhaust leak, I look under the car and can see a lot of heat coming out of the exhaust right next to fuel lines that now have no heatshield. It's as if he hadn't tightened it properly at all, the amount of air coming out is enough to move light dirt underneath the leak.

Is this the mechanics fault for not tightening properly, being next to fuel lines too with no heatshield must be unsafe? As a mechanic its his job to ensure the car he's working on leave his shop safe for a customer to drive.

I'm not looking to go after the mechanic, he just won't have my custom again. It's more the fact my dad swears by him and has done for years because it's easy for him.

[seqo]