Gaurav K. Goel, MDS

The advantage of composite veneers is that they can be easily modified/Repaired/ Replaced. In your case, you can talk to your dentist if he can modify them to your liking or else you may need to visit another one who would be more proficient at Esthetic composites. 

first thing you need is Xrays of these teeth. If these are indeed deciduous teeth, we need to check whether there are unerupted permanent teeth in the bone and whether they can be brought into place with braces. If that is possible, then its the best possible way. 

If there are no permanent teeth, or if present and they can be extracted, then implants would be the best option. 

If they cannot be removed then you have to go with FPD.

In general implants will be a better option than fpd. 

Although a detailed examination is required before assessing the feasibility and expected results, Your problem can be solved with Porcelain veneers. You may need to have 6 or 8 veneers on your front teeth.

Yes, there can be catastrophic results like caries and decay of the underlying or adjacent tooth, Gum problems, Bone loss, Etc. You should get it checked with an X-ray as soon as possible and if the marginal fit is questionable, get a new crown done.

Hi, with what i can see in the photos, it seems your husband needs a full mouth rehabilitation. You may check out some photos of FMR in my profile.
The cost of such treatment can be huge in the US so you may consider dental tourism to india.  we provide similar or better quality work at a fraction of the costs in the US and all work is done by Specialists using world class techniques and equipment.