My father has just brought a renault magane 03 plate.?

the problem is you use a card to start up the ignition and then press a on ,hes had it for 4 weeks and its sat in the drive way more than its been driven as it wont start at times or he can sit for more than 10 minutes before it will start , hes taken it back to the garage today to have a new part fitted what the garage said had gone , but when he got home he parked it up a while (half a hour ) then tried to start it up agian but took 15 minsto start .He is taking it back agian but i think the garage is fobbing him of as hes in his 70s and is not to bright anymore as he had 2 strokes within 5 weeks of each othere which affected his speeck and thinking and i think the garage realised this is pulling the wool over is eyes . Does any machanics have any idea why this is happening to the car ,hes getting very stressed and he doesnt need to be stressed, thanks.