Apologising for the lengthy reply…
Hi Poysyn. You don’t mention how old your older cat is. It does sound as if he is having behavior issues, possibly related to stress and/or illness. Bear in mind that illness and discomfort are stressful to animals (who cannot just rationalise it away, like, “Oh, that’s just my trick knee aching, it’ll be fine in a day so I’ll ignore it now” - all they know is it hurts and they can’t escape it.) So if your vet doesn’t find anything on thyroid testing (an excellent idea, since hyperthyroidism is fairly common in older cats and can cause behavioral changes, not to mention weight loss and hypertension and a variety of other problems), you might ask her to run a general health or geriatric screen. Several people have correctly pointed out that urniary tract problems can cause the cat to start avoiding the box (if it hurts when I pee in that box, I’ll just go pee somewhere else). However, there are other possibilities, which the blood screens will be a step toward ruling in or out.
(BTW, I’d like to go on record again to mention that urinary tract infections are NOT common in males cats, but are in females, and urinary tract obstruction, which is life-threatening and is a bona-fide, get me up at 2 A.M. and 40 below zero in an Alaskan January EMERGENCY, is just the opposite - common in males, rare in females.)
Reasons not to use the litter box include (besides urinary tract disorders) problems with the substrate (is the box cleaned frequently, and is the litter type one the cat prefers? Most cats like the clumping types best, but not all); problems with the box location or style (is it a covered box? one with a high edge? sufficiently roomy for an older and less-flexible cat? in a pleasant and accessable location for the cat? any changes - items moved away from or near to the box? new traffic pattern related to the box?); number of boxes or other animals in the house (the rule of thumb is one more box than you have cats in the house, and be aware that other animals, if present, may have begun ambushing this cat in his morning toilette, causing him to move elsewhere for his ablutions); household changes that are upsetting the cat’s sense of routine and security (such as schedule changes, new pets or people in the environment, old ones missing from the environment, construction/remodelling, packing or unpacking things, and even new animals in the neighborhood - they’re often aware of new animlas in the outdoor environment, even if they’re never outdoors). Covered litterboxes are a pain for a lot of cats, and if the edge is high and has to be stepped over, a cat with a little bit of ‘ouchy’ in the joints may prefer not to get into it, especially on first rising from a rest, when they are stiffest. Those cats often urinate next to the box - they know where to go, but they just can’t comfortably get in.
As for the meowing and clawing, that may be related to distress for physical reasons as well as psychological ones… if your cat is painful or ill, that may be a lot of it. Alternatively, he may be aware of the baby-related changes in the household and be feeling anxious (in which case some extra TLC will probably go a long way). We do see senility in cats, and there are some options for treatment for that and also for pain (be VERY careful not to give any painkillers to your cat unless the vet says to! cats can be killed by over the counter people meds!) There is a spray called Feliway that your vet may carry or be able to order… that’s used to decrease stress (it’s an analog of the pheromone that cats produce when they are content, and signals the brain that it’s time to be content now). We spray it in the cages of some of our pre-surgical cats who are stressing out. Seems to help, and some clients have reported good results.
You might also inquire, if all the bloods are normal, about whether or not Xrays would be helpful in tracking down underlying health problems, and whether or not there is a veterinary behaviorist in your area. A behaviorist will want the cat to have had a full medical workup, but some problems truly are behavioral and not medical.
Good luck with this… the longer you have them the more they’re part of the family, so I hope you and your vet are able to find a happy solution. And congratulations on your impending addition! An exciting and busy time for you right now; hopefully the kitty issues can be swiftly and happily laid to rest so you can concentrate on the fun parts.
