So sorry to hear of your loss
Sounds exactly to a tee what Nuggie was like after Tazi died. I could of read that and swore i'd written it!
It does improve - some cats quicker than others and even if they werent best of friends, Tipsy is also lost within her status. Once she adjusts she may feel a little more secure within her household again.
I adopted a young cat - this may not always be ideal, can be tad stressful, but some cats just need the company. Nuggie enjoys his new role of boss and certainly gives Peanut a run for his money. Peanut wonders whats wrong if Nuggie is too nice to him lol
Other times, once the grief and loss becomes less painful you may find Tipsy is content being an only cat.
Big hugs to you all