It wont reset if he accidentally logs in during the time he wasnt playing. It has to be a continuous long stretch from what i know.
Also he did not win the CL in the previous season which is in line with a returning player who would not have qualified for CL as well.
A tanking trophy collector usually wins it all.
If he is a tanker, what are his white skills like? 300s or at least above 200? For players like us who promote every season, even 200s and 300s are easy to maintain for attackers.
Go check out our moderators win loss records, you will be surprised how many losses they have. Perhaps they tank, i wouldnt know.