Does the memory impairment suffered by the questioner place him in a state of necessity or concession that permits him to deal with Islamic banks that trade in treasury bills?

If investing money means buying shares in banks that deal with usurious treasury bills, then this is not permissible. Weak memory or discontinuity of work does not permit dealing with usury except in cases of dire necessity according to Sharia (definition). However, if the intention is merely to place money in an investment account, please refer to the fatwas mentioned.