re: Legal advice - 403(b) plan

Couple of questions.
-Is mom still alive?
-was the account PoD (Pay on Death)?

If yes to the above, there should be no need for an estate (may not even need it for the 2nd item). The 403b should simply rollover to mom as his spouse.
If she has already passed, the LFG is correct. In this case you’ll need to go through the estate. This also has some different RMD requirements vs inheriting an IRA directly (5 year vs 10 year withdrawal).