Arthur Theory

We've all speculated wether arthur is dead or alive in the upcoming film, general consensus is that he's dead.

In season 6 finale arthur wrote a letter, read by linda, for Tommy and IIRC he said something like "the place you are going I will be there" or something along those lines.

It was 3 months after that point that Tommy discovered he wasn't sick after all.

What if arthur couldn't handle the thought of not having his brother and just killed himself? With Tommy being away 3 months in the wilderness there's a chance he never found out about his death till after.

What do you guys think?